BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

12 Months Ended

Dec. 31, 2025

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Principles of Consolidation

Principles of Consolidation – The consolidated financial statements include the accounts of Sun Country Airlines Holdings, Inc. and its subsidiaries and have been prepared in accordance with U.S. GAAP. All material intercompany balances and transactions have been eliminated in consolidation.

Fiscal Year

The Company operates its fiscal year on a calendar year basis.

Use of Estimates

Use of Estimates – The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, revenues and expenses and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates. Significant areas of judgment relate to passenger revenue recognition, maintenance under the built-in overhaul method, lease accounting, impairment of long-lived and other intangible assets, and air traffic liabilities.

Revenue Recognition

Revenue Recognition – Scheduled Service, Charter, and most ancillary revenues are recognized when the passenger flight occurs. Revenues exclude amounts collected on behalf of other parties, including transportation taxes.

Scheduled Service. The Company initially defers ticket sales as an Air Traffic Liability and recognizes revenue when the passenger flight occurs. Unused non-refundable tickets expire at the date of scheduled travel and are recorded as revenue unless the customer notifies the Company in advance of such date that the customer will not travel. If notification is made, a travel credit is created for the face value, including ancillary fees, less applicable change fees. Travel credits may generally be redeemed toward future travel for up to 12 months after the date of the original booking. Therefore, these credits are recorded as a current liability on the Company's Consolidated Balance Sheets. The Company records an estimate for travel credits that will expire unused, otherwise known as breakage, in Passenger Revenue upon issuance of the travel credit. The estimated breakage rate is primarily based on historical experience of travel credit activity and other factors that may not be indicative of future trends, such as program changes or modifications that could affect the ultimate usage patterns of tickets and travel credits. The Company continuously monitors its breakage rate assumptions and may adjust its estimated breakage rate in the future. Changes in the Company’s estimated breakage rate impact revenue recognition prospectively. The Company currently accounts for direct selling costs, including credit card fees, and commissions, in accordance with the terms of each service. The expense is deferred and recognized when the travel occurs.

Ancillary. Ancillary revenue consists primarily of revenue generated from air travel-related services such as baggage fees, seat selection and upgrade fees, priority check-in and boarding fees, other fees and on-board sales, which are recognized when the associated flight occurs. Revenue for change fees is deferred and recognized when the passenger travel occurs. Fees received in advance of the flight date are initially recorded as an Air Traffic Liability.

Charter. Our Charter business includes ad hoc, repeat, short-term and long-term service contracts that typically include pass-through fuel arrangements. Under these Charter agreements, the Company is obligated to provide aircraft, crew, maintenance, and insurance for travel. Customers are generally responsible for aircraft fuel, transportation taxes, and certain other flight expenses, which are typically arranged by the Company. When functioning as the customers' agent for arranging such services, the Company records amounts reimbursable from the customer as revenues, net of the associated costs incurred to fulfill the performance obligations. In certain situations, the Company may be responsible for the aforementioned costs and is reimbursed by the customer. In these situations, the Company is the principal. The reimbursed costs are recognized as revenue and the costs are recognized as expenses on the Company's Statement of Operations.

Revenue is recognized as the services are performed based on Block Hours operated on behalf of customers. The costs of obtaining the Company's Charter contracts are not material.

Cargo. In December 2019, the Company signed the ATSA with Amazon. In June 2024, the Company entered into the A&R ATSA with Amazon that increased the number of Boeing 737-800 cargo aircraft that Sun Country operates on behalf of Amazon from 12 to 20 in 2025. During 2025, all eight additional aircraft were received and placed in-service. In early 2026, the Company agreed to operate another two additional cargo aircraft on behalf of Amazon. This will increase the total aircraft that Sun Country operates on behalf of Amazon from 20 to 22. The A&R ATSA includes an initial six-year term, which expires in October 2030. The agreement includes two additional, two-year renewal terms exercisable at Amazon's option, and a subsequent three-year renewal term subject to mutual written agreement, which, if not agreed to, will trigger a final two-year wind-down term. The ATSA has annual rate escalations.

The A&R ATSA contains three performance obligations: Flight Services, Heavy Maintenance and Fuel; all of which are unchanged from the original ATSA. As Sun Country is the principal in providing Flight Services, revenue and related costs are recognized gross on the Statement of Operations. Sun Country acts as the agent in providing the Heavy Maintenance and Fuel performance obligations, which are reimbursed by Amazon based on the actual costs incurred. Consumption of aircraft fuel and heavy maintenance are recognized in revenue, net of the associated costs incurred to fulfill the performance obligations.

The A&R ATSA with Amazon consists of three main components of consideration, which are unchanged from the original ATSA; a fixed amount is received each month per aircraft, a fixed amount is received each month per flight, and an amount per block hour is received each month. The A&R ATSA contains a SLA and penalties for certain delays and cancellations. The SLA can result in a bonus or penalty for the month depending on the Company's performance. The economics of the three main components of consideration and the SLA for the A&R ATSA have been revised from the original ATSA. When determining the transaction price, the Company will estimate the variable consideration and consideration payable to Amazon over the contract term. Each period, the Company updates its estimate for the variable consideration and consideration payable to the customer and treats the adjustment as an adjustment to the transaction price. When updating the estimate, the Company considers whether there are any changes in expected block hours, changes in expected bonuses or penalties based on performance, changes in warrants expected to be issued, and changes in reimbursable costs. The transaction price is allocated to the performance obligations based on their relative standalone selling price. The transaction price for Flight Services, which includes an upfront payment for startup costs, is reduced by the estimated value of warrants to be issued to Amazon based on expected performance under the A&R ATSA.

Loyalty Program Accounting

Loyalty Program Accounting – The Company records a liability for loyalty points earned by passengers under its Sun Country Rewards program using two methods: 1) a liability for points that are earned by passengers on

purchases of the Company’s services is established by deferring revenue based on the redemption value net of breakage, and 2) a liability for points attributed to loyalty points issued to the Company’s co-branded credit card holders is established by deferring a portion of payments received from the Company’s co-branded agreement.

The Company’s Sun Country Rewards program allows for the redemption of loyalty points to include payment towards air travel, taxes, and other ancillary purchases. The Company determines the standalone selling price of loyalty points issued using a redemption value approach, which considers the value a passenger will receive upon redemption of the loyalty points. Consideration allocated to loyalty points is deferred, net of estimated breakage, and recognized as Passenger Revenue when both the loyalty points have been redeemed and the passenger travel occurs. The Company estimates breakage for loyalty points that are not likely to be redeemed. These estimates are based on historical experience of loyalty point redemption activity and other factors, such as program changes and modifications that could affect the ultimate usage pattern of loyalty points. The current portion of the Loyalty Point Liability is an estimate based on historical redemption patterns over the past 12 months.

The Company also maintains a co-branded Credit Card Program. In March 2025, the Company entered into a new Credit Card Program, which launched in the third quarter of 2025. Subject to certain exceptions, the Credit Card Program has a term of seven years following its launch. Individuals with a co-branded Sun Country credit card receive points for spend incurred on the co-branded credit card, as well as additional elements. These elements include one free alcoholic beverage per flight, 50% discount on seat selection fees, 50% discount on baggage fees, 25% off in-flight food and beverage purchases, as well as priority boarding. The Company is responsible for providing these goods and services.

Under the Company's co-branded credit card program, funds received for the marketing of a co-branded credit card, delivery of additional elements, and delivery of loyalty points are accounted for as a multiple-deliverable arrangement. The arrangement has three distinct performance obligations: loyalty points to be awarded, brand and marketing, and additional elements (which is inclusive of the ancillary products described above). Funds received are allocated between the performance obligations on a relative standalone selling price. Revenue for the brand and marketing performance obligation is recognized as revenue when earned and recorded in Other Revenue. Consideration allocated to the additional elements is recognized as revenue when earned and recorded within Ancillary Revenue. Consideration allocated to loyalty points is deferred and recognized as Passenger Revenue when both the loyalty points have been redeemed and the passenger travel occurs.

Cash and Equivalents

Cash and Equivalents – The Company considers all highly liquid investments with an original maturity of three months or less to be cash equivalents, including certificates of deposit with maturities less than 90 days. The Company maintains cash balances at several financial institutions; at times, such balances may be in excess of insurance limits. The Company has not experienced any losses on these balances.

Restricted Cash

Restricted Cash – The Company's Restricted Cash balance primarily relates to Charter revenue receipts received prior to the date of transportation. These amounts are also recorded as a component of the Company's Air Traffic Liabilities. DOT regulations require that Charter revenue receipts received prior to the date of transportation are maintained in a separate third-party escrow account. The restrictions are released once transportation is provided, which is typically within 12 months of booking. For that reason, the balance of Restricted Cash is classified as a current asset on the Company's Consolidated Balance Sheets.

Investments

Investments – The Company's investments consist of Debt Securities and Certificates of Deposit with maturities greater than 90 days. The Certificates of Deposit are recorded at cost, plus accrued interest. These certificates serve as collateral for letters of credit required by various airports and other vendors.

The Debt Securities are classified as Current Assets on the Consolidated Balance Sheets because the securities are highly liquid and are available to be quickly converted into known amounts of cash to fund current operations. These investments have original maturities of three months or greater. As of December 31, 2025, all of the Company's outstanding Debt Securities will mature by June 2027. The Company limits its exposure to any one issuer or market sector and largely limits its investments to investment grade quality securities.

Securities downgraded below policy minimums after purchase will be disposed of in accordance with the Company’s investment policy.

The Company's Debt Securities are classified as Available-for-Sale and are reported at fair value on the Company's Consolidated Balance Sheets. Unrealized gains and losses on the Company's Available-for-Sale securities are excluded from Net Income and are reported as a component of Accumulated Other Comprehensive Income, net of income tax effects, within Stockholders' Equity on the Consolidated Balance Sheets until realized. Realized gains and losses are recorded using the specific identification method and reflected in Other, net within Non-operating Income (Expense), net on the Company's Consolidated Statement of Operations. The Company did not realize any gains or losses on its Available-for-Sale investments for the years ended December 31, 2025, 2024 and 2023. Premiums and discounts recorded on Available-for-Sale debt securities are accounted for in Interest Income within Non-operating Income (Expense), net on the Company's Consolidated Statement of Operations.

At each reporting period, the Company assesses its Available-for-Sale investments in an unrealized loss position to determine whether an impairment exists. The Company will record an impairment if management intends to sell an impaired security, will likely be required to sell a security before recovery of the entire amortized cost, or the same level of collectible cash flows from the security is no longer expected. The entire impairment will be included in Other, net within Non-operating Income (Expense), net on the Company's Consolidated Statement of Operations.

Accounts Receivable

Accounts Receivable – Accounts Receivable are recorded at the amount due from customers and do not bear interest. They consist primarily of amounts due from Amazon, credit card companies associated with ticket sales and Charter customers. The Company's Accounts Receivable balances at December 31, 2025 and 2024 also included $3,639 and $612, respectively, due from aircraft lessors related to maintenance deposits. Accounts outstanding longer than the contractual payment terms are considered past due. The Company determines its allowance for credit losses by considering a number of factors, including the length of time accounts receivable are past due, the Company’s previous loss history, the customer’s current ability to pay its obligation to the Company, and the condition of the general economy and the industry as a whole.

Lessor Maintenance Deposits

Lessor Maintenance Deposits – Certain of the Company’s aircraft lease agreements provide that the Company pay maintenance reserves monthly to aircraft lessors to be held as collateral in advance of major maintenance activities required to be performed by the Company. Generally, maintenance reserve payments are variable based on actual flight hours or cycles. These lease agreements provide that maintenance reserves are reimbursable to the Company upon completion of the maintenance event in an amount equal to the lesser of (1) the amount of the maintenance reserve held by the lessor associated with the specific maintenance event or (2) the qualifying costs related to the specific maintenance event.

Maintenance reserve payments that are expected to be recoverable via reimbursable expenses are reflected as Lessor Maintenance Deposits on the accompanying Consolidated Balance Sheets. These deposits are expected to be reimbursed to the Company upon performance of maintenance activities. Upon completion of the maintenance event, the lessor is billed and the amount due is recorded in Accounts Receivable. Lessor Maintenance Deposits deemed improbable of recovery are expensed as incurred and recorded within Aircraft Rent.

The Company makes certain assumptions at the inception of the lease and at each Balance Sheet date to determine the recoverability of maintenance deposits. These assumptions are based on various factors, such as the estimated time between the maintenance events, the cost of such maintenance events, the date the aircraft is due to be returned to the lessor, and the estimated number of flight hours and cycles the aircraft is to be utilized before it is purchased or returned to the lessor. Changes in estimates are accounted for on a prospective basis. As of December 31, 2025, all maintenance deposits are estimated to be recoverable either through reimbursable maintenance events or through application towards the purchase of the aircraft.

Inventory

Inventory – Inventory primarily consist of expendable parts related to flight equipment, which cannot be economically repaired, reconditioned or reused after removal from the aircraft, are carried at average cost and charged to operations as consumed. An allowance for obsolescence and excess is provided over the remaining useful life of the related fleet for spare parts expected to be on hand at the date that aircraft type is retired from service. These parts are assumed to have an estimated residual value of 10% of the original cost.

Leases

Leases – Lease classification is evaluated by the Company at lease commencement and when significant amendments are executed. The Company's leases generally do not provide a readily determinable implicit rate; therefore, the Company estimates the incremental borrowing rate to discount lease payments based on information available at lease commencement. The lease term consists of the noncancellable period of the lease and periods covered by options to extend the lease if the Company is reasonably certain to exercise the option. For leases of 12 months or less, the Company expenses lease payments on a straight-line basis over the lease term.

Operating Lease Right-of-Use Asset and Liabilities

For all operating leases with a term greater than 12 months, the Company recognizes a right-of-use asset and a lease liability at the lease commencement date based on the estimated present value of future minimum lease payments, which includes certain lease and non-lease components, over the lease term. Operating Lease Right-of-use Assets and Operating Lease Obligations have their own lines on the Consolidated Balance Sheets.

Finance Leases

Finance leases are initially recorded at the net present value of future minimum lease payments, which includes certain lease and non-lease components. Finance leases generally have one of these five attributes: 1) ownership of the underlying asset transfers to the Company at the end of the lease term, 2) the lease agreement contains a purchase option that the Company is reasonably certain to exercise, 3) the lease term represents the major part of the asset’s economic life, 4) the present value of lease payments over the lease term equals or exceeds substantially all of the fair value of the asset, and 5) the underlying asset is so specialized in nature that it provides no alternative use to the lessor after the lease term. Finance Lease Assets are presented separately on the Consolidated Balance Sheets. The Company depreciates Finance Lease Assets consistent with its useful life policy presented within "Property & Equipment".

Leased Aircraft Return Costs

The Company's aircraft lease agreements often contain provisions that require the Company to return aircraft airframes, engines, and other aircraft components to the lessor in a certain condition or pay an amount to the lessor based on the airframe and engine's actual return condition. Lease return costs are recognized beginning when it is probable that such costs will be incurred and they can be estimated. The Company assesses the need to accrue lease return costs periodically throughout the year or whenever facts and circumstances warrant an assessment. When costs become both probable and estimable, lease return costs are expensed on the Consolidated Statements of Operations.

Property & Equipment

Property & Equipment – Property and equipment are recorded at cost or fair value on the date of acquisition and depreciated, when the asset is ready for its intended use, on a straight-line basis to an estimated residual value over their estimated useful lives or lease term (if applicable), whichever is shorter, as follows:

Airframes (1)	10-25 years (depending on age)
Engines – Core (2)	7 or 12 years (based on remaining cycles)
Engines – Initial Greentime (time remaining until the first scheduled major maintenance event)	1st scheduled maintenance event
Leasehold Improvements, Aircraft, Other	3-25 years (or life of lease, if shorter)
Office and Ground Equipment	5-7 years
Computer Hardware and Software	3-5 years
Property and Equipment under Finance Leases (3)	Lesser of the lease term or economic life
Rotable Parts	Average remaining life of aircraft fleet, currently estimated to be 8 years

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(1)	Airframes have an estimated residual value of $4,000.
(2)	Engines - Core have an estimated residual value of $1,500.
(3)	For finance leases where the Company is reasonably certain to exercise the purchase option, the lease asset value is assigned to the engine and airframe components which are depreciated on a straight-line basis in accordance with the useful lives outlined in the table above.

Our tangible assets consist primarily of Aircraft and Flight Equipment, which are mobile across geographic markets. Therefore, assets are not allocated to specific geographic regions.

Modifications that enhance the operating performance or extend the useful lives of leased airframes are considered leasehold improvements and are capitalized and depreciated over the economic life of the asset or the term of the lease, whichever is shorter. Similar modifications made to owned aircraft are capitalized and depreciated consistent with the Company’s policy.

The Company capitalizes certain internal and external costs associated with the acquisition and development of internal-use software for new products, and enhancements to existing products, that have reached the application development stage and meet recoverability tests. Capitalized costs include external direct costs of materials and services utilized in developing or obtaining internal-use software, and labor cost for employees who are directly associated with, and devote time to, internal-use software projects.

The Company depreciates Rotable Parts to an estimated residual value using the pooling life method. Depreciation under the pooling life method is calculated over the estimated average useful life of the passenger aircraft fleet.

The Company capitalizes certain costs of activities necessary to get the asset ready for its intended use. Capitalized interest represents interest costs incurred during the aircraft induction period, capitalization ceases when the asset is ready for service.

Airframe and Engine Maintenance

Airframe and Engine Maintenance – The Company accounts for non-major maintenance and repair costs incurred, as well as major maintenance costs of owned airframes, all leased airframes, and engines acquired via operating leases, using the expense as incurred method. Certain costs covered by third-party maintenance agreements are charged to expense based on fleet utilization, as defined by the contract. These expenses are reported as a component of Maintenance expense on the accompanying Consolidated Statements of Operations.

The Company applies the built-in overhaul method for significant maintenance costs of owned engines, as well as to engines acquired via finance leases where the Company is reasonably certain to exercise a purchase option. Under this method, engine values are separated into amounts for life limited parts and “greentime”, representing the value of the engine for the time on-wing remaining until the next anticipated major maintenance event. Life limited parts are capitalized based on catalog rates published by the original equipment manufacturer and depreciated over their estimated useful lives. Initial engine "greentime" and subsequent major engine maintenance events are capitalized and depreciated until the next anticipated major maintenance event, assuming no residual value. The period until the next scheduled major maintenance event is estimated based on assumptions such as estimated cycles, hours, and months, required maintenance intervals, and the age/condition of related parts. These assumptions may change based on forecasted aircraft utilization changes, updates to government regulations and manufacturer maintenance intervals, as well as unplanned incidents causing damage requiring a major maintenance event prior to a scheduled visit. If the estimated timing of the next maintenance event changes, the related depreciation period changes prospectively. These expenses are reported as a component of Depreciation and Amortization on the accompanying Consolidated Statements of Operations.

Maintenance Rights Asset

Maintenance Rights Asset - During the year ended December 31, 2023, the Company acquired five Boeing 737-900ERs that at the time of purchase were on lease to an unaffiliated airline. Upon purchase of the Owned Aircraft Held for Operating Lease, the Company recognized a Maintenance Rights Asset which represents the Company’s contractual right to receive the aircraft in a specified maintenance condition at the end of the lease. The acquired leases contain an end of lease compensation clause whereby the lessee is required to perform the maintenance tasks needed to physically restore the airframe and engines to full-life condition or remit a cash payment to compensate the Company for the maintenance shortfall. The asset represents the difference between the Owned Aircraft Held for Operating Lease’s physical maintenance condition as of the purchase date and the contractual return condition at the end of the lease term. The Maintenance Rights Asset is not depreciated over the lease term, nor will it accrete as additional life is consumed on the aircraft.

Subsequent accounting for the Maintenance Rights Asset will occur at the end of the lease term when the end of lease compensation has been settled between the Company and the unaffiliated lessee. One of the following scenarios will occur based on the underlying facts and circumstances: 1) the aircraft is returned at lease expiry in the contractually specified maintenance condition without any cash payment to the Company by the lessee, the Maintenance Rights Asset is relieved, and an aircraft improvement asset is recorded to the extent the improvement is substantiated and deemed to meet the Company’s capitalization policy; 2) the lessee pays the Company cash compensation at lease expiry in excess of the value of the Maintenance Rights Asset, the excess is recognized as revenue and presented within Other Revenue on the Consolidated Statements of Operations; or 3) the lessee pays the Company cash compensation at lease expiry that is less than the value of the Maintenance Rights Asset, the shortfall is recorded as an aircraft improvement asset to the extent the improvement is substantiated and meets the Company’s capitalization policy, if it does not meet capitalization criteria the shortfall is recognized as an expense within Maintenance on the Consolidated Statements of Operations. Any aircraft improvement will be applied at the aircraft component level, will be depreciated in accordance with the Company’s policy and reported as a component of Depreciation and Amortization on the accompanying Consolidated Statements of Operations.

Asset Impairment Analysis

Asset Impairment Analysis – Long-lived assets, such as Property & Equipment and finite-lived Other Intangible Assets, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset (or asset group) may not be recoverable. If circumstances require a long-lived asset or asset group be tested for impairment, the Company first compares the undiscounted cash flows expected to be generated by that asset or asset group to its carrying amount. If the carrying amount of the long-lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds its fair value. Fair value is determined using various valuation

techniques including discounted cash flow models, quoted market values and third-party independent appraisals, as considered necessary.

Goodwill and Other Intangible Assets

Goodwill and Other Intangible Assets – Goodwill represents the excess purchase price over the estimated fair value of net assets acquired in a business combination. Other Intangible Assets with Indefinite Lives represents a tradename acquired in a business combination. Other Intangible Assets with Finite Lives represent customer relationships acquired in a business combination and over-market lease assets acquired when the Company purchased five Owned Aircraft Held for Operating Lease. Goodwill and Other Intangible Assets with Indefinite Lives must be tested for impairment at least annually, or more frequently if events or changes in circumstances indicate that they might be impaired. Goodwill is tested at the reporting unit level. The Company has two reporting units: Passenger and Cargo. All of the Company's Goodwill balance is associated with the Passenger reporting unit.

Other Intangible Assets with Finite Lives are amortized over an estimated useful life. The estimated useful life for the Company's customer relationship intangible asset was based on several factors, including the effects of demand, competition, contractual relationship, and other business factors. The Company concluded that the customer relationships Other Finite-lived Intangible Asset has an estimated life of 12 years and is being amortized over this period on a straight-line basis. The Company's over-market lease asset will be amortized over the remaining lease terms for the respective aircraft. As of December 31, 2025, the remaining leases expire over various dates through the fourth quarter of 2026.

The value of Goodwill and Other Indefinite-lived Intangible Assets is assessed under either a qualitative or quantitative approach. Under a qualitative approach, the Company considers various market factors, including certain key assumptions, such as the market value of the airline and other airlines, fuel prices, the overall economy, passenger yields and changes to the regulatory environment. The Company analyzes these factors to determine if events and circumstances have affected the fair value of Goodwill and Other Indefinite-lived Intangible Assets. If it is determined that it is more likely than not that the asset may be impaired, the Company uses a quantitative approach to determine the reporting unit or intangible asset’s fair value incorporating the key assumptions listed below. An impairment charge is recorded for the amount of carrying value that exceeds the determined fair value as of the testing date.

When the Company evaluates Goodwill or its Other Indefinite-lived Intangible Assets for impairment using a quantitative approach, the Company utilizes market and income approach valuation techniques. These measurements include the following key assumptions, 1) forecasted revenues, expenses and cash flows, 2) current discount rates, 3) comparative market multiples, 4) observable market transactions, and 5) anticipated changes to the regulatory environment. These assumptions are consistent with those that hypothetical market participants would use. Because the Company is required to make estimates and assumptions when evaluating Goodwill and Other Indefinite-lived Intangible Assets for impairment, actual transaction amounts may differ materially from these estimates.

The Company performed its most recent annual Goodwill and Other Indefinite-lived Intangible Assets impairment analysis as of October 1, 2025.

Income Taxes

Income Taxes – Deferred income taxes are recognized for the tax consequences in future years of differences between the tax basis of assets and liabilities and their financial reporting amounts at each year end based on enacted tax laws and statutory tax rates applicable to the periods in which the differences are expected to affect taxable income. Valuation allowances are established when necessary to reduce Deferred Tax Assets to the amount expected to be realized. All Deferred Tax Assets and Liabilities, along with any related valuation allowance, are classified as noncurrent on the Consolidated Balance Sheets. Interest and penalties on uncertain tax positions, to the extent they exist, are included in the Company’s provision for income taxes. The

provision for income taxes represents the current tax expense for the period and the change during the period in Deferred Tax Assets and Liabilities.

TRA Liability

TRA Liability – In connection with the Company’s IPO, the legal entity Sun Country Airlines Holdings, Inc. entered into a TRA with the pre-IPO stockholders (the “TRA holders”, which includes certain members of the Company's management and certain members of the Company's Board of Directors.). The TRA provides for the payment by the Company to the TRA holders of 85% of the amount of cash savings, if any, in U.S. federal, state, local, and foreign income tax that the Company actually realizes (or is deemed to have realized in certain circumstances) as a result of certain tax attributes that existed at the time of the IPO (the “Pre-IPO Tax Attributes”). The Company will retain the benefit of the remaining 15% of these cash savings.

Future adjustments in the TRA Liability balance and/or timing of TRA Liability payments are contingent upon, among other things, 1) generation of future taxable income over the term of the TRA, 2) the Company’s participation in future government programs, and 3) future changes in tax laws. All adjustments to the TRA Liability were recorded in Other, net within Non-Operating Income (Expense), net in the Company’s Consolidated Statements of Operations.

The Company began making TRA payments during the year ended December 31, 2023. TRA payments are classified as Financing Activities in the Company's Consolidated Statement of Cash Flows. The portion of the TRA expected to be paid in the next 12 months is reflected as a current liability on the Consolidated Balance Sheets. All other amounts are reflected as a non-current liability on the Consolidated Balance Sheets. In the case of a merger that constitutes a change of control, such as the Merger Agreement with Allegiant, the TRA will terminate. Upon completion of the potential Merger with Allegiant, the TRA will be settled with the TRA holders. The amount paid to the TRA holders will be the outstanding balance of the TRA at time of closing.

Aircraft Fuel

Aircraft Fuel - The Company’s operations are inherently dependent upon the price of aircraft fuel. Aircraft fuel expense includes jet fuel, federal and state taxes, and other fees

Sales And Marketing

Sales and Marketing - Sales and Marketing expense includes credit card processing fees, travel agent commissions and related global distribution systems fees, advertising, sponsorship and distribution costs, such as the costs of our call centers, and costs associated with our loyalty program. The Company expenses advertising costs as incurred.

Equity Incentive Plan

Equity Incentive Plan – Under its Equity Incentive Plan, the Company has primarily issued Time-Based Stock Options, Performance-Based Stock Options, Restricted Stock, PRSUs, and RSU awards. Further, the Company has elected to account for forfeitures as they occur, rather than forecasting the future forfeitures. If an award is forfeited prior to vesting, the associated reduction in expense is reflected net in stock-based compensation expense in that period. Stock compensation expense is reported as a component of Salaries, Wages, and Benefits within the Company's Consolidated Statement of Operations.

Earnings per Share

Earnings per Share - Basic earnings per share, which excludes dilution, is computed by dividing Net Income available to common stockholders by the weighted average number of shares of common stock outstanding for the period. Diluted earnings per share reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock. The number of incremental shares from the assumed issuance of shares relating to securities or other contracts to issue common stock is calculated by applying the treasury stock method. The treasury stock method assumes a hypothetical issuance of shares to settle the securities or other contracts to issue common stock, with the assumed proceeds used to purchase common stock at the average market price for the period. Assumed proceeds include the amount to be paid upon exercise, if applicable, and the average unrecognized compensation cost. The difference between the number of shares assumed issued and the number of shares assumed purchased represents the dilutive shares.

Warrants held by Amazon are included in the calculation of dilutive weighted average shares outstanding as of the date the warrants vest to the extent the impact is dilutive. The unvested warrants have not been included in dilutive shares as their performance condition has not been satisfied.

Concentration Risk

Concentration Risk

Approximately 55% and 25% of the Company’s Accounts Receivable balances as of December 31, 2025, and 2024 were due from Amazon, respectively. In addition, approximately 9% and 13% of the Company’s Accounts Receivable balances as of December 31, 2025 and 2024, were due from one financial institution for tickets purchased via credit cards.

Approximately 46% and 45% of the Company's fuel purchases were made from two vendors that each had fuel purchases representing 10% or more of the Company's total fuel purchases for the years ended December 31, 2025 and 2024, respectively. Approximately 59% of the Company's fuel purchases were made from three vendors that each had fuel purchases representing 10% or more of the Company's total fuel purchases for the year ended December 31, 2023.

Approximately 66% of the Company’s workforce were under union contracts as of December 31, 2025 with four different unions: ALPA, IBT, TWU and AMFA. As of December 31, 2025, approximately 31% of the Company’s union workforce are under contracts that are being negotiated, have become amendable or will expire within the next year.

Recently Adopted Accounting Standards and Recently Issued Accounting Standards

Recently Adopted Accounting Standards

In December 2023, the Financial Accounting Standards Board issued Accounting Standards Update ("ASU") 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This ASU requires, among other disclosures, greater disaggregation of information, the use of certain categories in the rate reconciliation, and the disaggregation of income taxes paid by jurisdiction. On December 31, 2025, the Company adopted this standard retrospectively. See Note 14 included within these Consolidated Financial Statements for the incremental disclosures, as required.

Recently Issued Accounting Standards

In November 2024, the FASB issued ASU 2024-03, Disaggregation of Income Statement Expenses. This ASU requires disaggregated disclosure of income statement expenses for public business entities. The ASU does not change the expense captions an entity presents on the face of the Statement of Operations; rather, it requires disaggregation of certain expense captions into specified categories in disclosures within the footnotes of the financial statements. The ASU is effective for public business entities for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027, with early adoption permitted. The Company continues to assess the impact of this ASU on its Consolidated Financial Statements.

In May 2025, the FASB issued ASU 2025-04, Clarifications to Share-Based Consideration Payable to a Customer. This ASU clarifies the definition of "performance condition" and in cases of awards with service conditions, eliminates the policy election permitting a grantor to account for forfeitures as they occur. The ASU is effective for public business entities for fiscal years beginning after December 15, 2026, and interim periods within those fiscal years, with early adoption permitted. The Company continues to assess the impact of this ASU on its Consolidated Financial Statements.

In September 2025, the FASB issued ASU 2025-06, Targeted Improvements to the Accounting for Internal-Use Software. This ASU requires entities to capitalize software costs when both of the following occur: management

has authorized and committed to funding the software project, and it is probable that the project will be completed and the software will be used to perform the function intended. Entities may adopt this standard using one of three approaches: a prospective transition, a modified transition based on the status of the project and whether software costs were capitalized before the date of adoption, or a retrospective transition. The ASU is effective for public business entities for fiscal years beginning after December 15, 2027, and interim periods within those fiscal years, with early adoption permitted as of the beginning of an annual reporting period. The Company continues to assess the impact of this ASU on its Consolidated Financial Statements.