Related-Party Transactions	12 Months Ended
Dec. 31, 2021
Related Party Transactions [Abstract]
Related-Party Transactions	10. RELATED‑PARTY TRANSACTIONS Aircraft Lease—On August 30, 2014, a related party, Moelis & Company Manager LLC ("Manager"), acquired an aircraft with funds received solely from its managing member (Mr. Moelis). The aircraft was used and operated by the Company pursuant to a dry lease with Manager. The terms of the dry lease were comparable to the market rates of leasing from an independent third party. Pursuant to this dry lease arrangement, the lessee is obligated to bear its share of the costs of operating the aircraft. In addition, Mr. Moelis was the other lessee of the aircraft and shared the operating and related costs of the plane in proportion to his respective use pursuant to a cost sharing and operating agreement. On July 12, 2019, the Company terminated its aircraft dry lease with Manager, the lessor, and Mr. Moelis, the other lessee (the “Old Lease”) and the related cost sharing agreement with Mr. Moelis, which were set to expire by their terms on December 31, 2019, and entered into a new dry lease with Manager, the lessor, and Mr. Moelis, the other lessee (the “New Lease”) and cost sharing agreement with Mr. Moelis, which terminate on December 31, 2022. The terms of the New Lease and new cost sharing agreement are substantially similar to the Old Lease and related cost sharing agreement. For the years ended December 31, 2021, 2020, and 2019, the Company incurred $1,295, $1,295 and $1,674 in aircraft lease costs to be paid to Manager, respectively. Promissory Notes—As of December 31, 2021, there were $219 of unsecured promissory notes from employees held by the Company (December 31, 2020: $389). Any outstanding balances are reflected in accrued and other receivables on the consolidated statements of financial condition. The notes held bear fixed interest rates ranging from 3.00% to 4.00%. During the years ended December 31, 2021, 2020 and 2019, the Company received $70, $0 and $0, respectively, of principal repayments and recognized interest income of $11, $12 and $8, respectively, on such notes, respectively, which is included in other income and expenses on the consolidated statements of operations. During the year ended December 31, 2021, the Company recognized $100 of compensation and benefits expense related to a tranche of a promissory note that will not be repaid. Services Agreement—In connection with the Company’s IPO, the Company entered into a services agreement with a related party, Moelis Asset Management LP, whereby the Company provides certain administrative services to Moelis Asset Management LP for a fee. This fee totaled $220, $296 and $248 for the years ended December 31, 2021, 2020 and 2019, respectively. The amount of the fee is based upon the estimated usage and related expense of all shared services between the Company and Moelis Asset Management LP during the relevant period, and will be assessed periodically by management as per the terms of the agreement. As of December 31, 2021 and 2020, the Company had no balances due to or from Moelis Asset Management LP. Affiliated SPACs and SPAC Sponsors—The Company provides office space, secretarial, administrative, and other corporate services to Atlas Crest Entities. These services are provided to the Atlas Crest Entities upon consummation of their IPOs, in each case for a fee of $10 per month. For the years ended December 31, 2021 and December 31, 2020, this fee totaled $200 and $20, respectively. This arrangement shall continue with each Atlas Crest Entity until such Atlas Crest Entity consummates a business combination or is liquidated. As of December 31, 2021 and December 31, 2020, the Company had no balances due from the Atlas Crest Entities or their sponsors. MA Financial—As of December 31, 2021 and 2020, the Company had net balances of $0 and $5 due to MA Financial, respectively, which is reflected in accrued and other receivables on the consolidated statements of financial condition. These balances consist of amounts due to or from MA Financial for advisory services performed as well as billable expenses incurred by the Company on behalf of MA Financial during the period. The relationship between the Company and MA Financial is governed by a services agreement. Revenues—From time to time, the Company enters into advisory transactions with affiliated entities, such as an Atlas Crest Entity or Moelis Asset Management LP and its affiliates. The Company earned revenues associated with such transactions of $30,346, $0 and $210 for the years ended December 31, 2021, 2020 and 2019, respectively.

Related-Party Transactions

12 Months Ended

Dec. 31, 2021

10.

RELATED‑PARTY TRANSACTIONS

Aircraft Lease—On August 30, 2014, a related party, Moelis & Company Manager LLC ("Manager"), acquired an aircraft with funds received solely from its managing member (Mr. Moelis). The aircraft was used and operated by the Company pursuant to a dry lease with Manager. The terms of the dry lease were comparable to the market rates of leasing from an independent third party. Pursuant to this dry lease arrangement, the lessee is obligated to bear its share of the costs of operating the aircraft. In addition, Mr. Moelis was the other lessee of the aircraft and shared the operating and related costs of the plane in proportion to his respective use pursuant to a cost sharing and operating agreement. On July 12, 2019, the Company terminated its aircraft dry lease with Manager, the lessor, and Mr. Moelis, the other lessee (the “Old Lease”) and the related cost sharing agreement with Mr. Moelis, which were set to expire by their terms on December 31, 2019, and entered into a new dry lease with Manager, the lessor, and Mr. Moelis, the other lessee (the “New Lease”) and cost sharing agreement with Mr. Moelis, which terminate on December 31, 2022. The terms of the New Lease and new cost sharing agreement are substantially similar to the Old Lease and related cost sharing agreement.

For the years ended December 31, 2021, 2020, and 2019, the Company incurred $1,295, $1,295 and $1,674 in aircraft lease costs to be paid to Manager, respectively.

Promissory Notes—As of December 31, 2021, there were $219 of unsecured promissory notes from employees held by the Company (December 31, 2020: $389). Any outstanding balances are reflected in accrued and other receivables on the consolidated statements of financial condition. The notes held bear fixed interest rates ranging from 3.00% to 4.00%. During the years ended December 31, 2021, 2020 and 2019, the Company received $70, $0 and $0, respectively, of principal repayments and recognized interest income of $11, $12 and $8, respectively, on such notes, respectively, which is included in other income and expenses on the consolidated statements of operations. During the year ended December 31, 2021, the Company recognized $100 of compensation and benefits expense related to a tranche of a promissory note that will not be repaid.

Services Agreement—In connection with the Company’s IPO, the Company entered into a services agreement with a related party, Moelis Asset Management LP, whereby the Company provides certain administrative services to Moelis Asset Management LP for a fee. This fee totaled $220, $296 and $248 for the years ended December 31, 2021, 2020 and 2019, respectively. The amount of the fee is based upon the estimated usage and related expense of all shared

services between the Company and Moelis Asset Management LP during the relevant period, and will be assessed periodically by management as per the terms of the agreement. As of December 31, 2021 and 2020, the Company had no balances due to or from Moelis Asset Management LP.

Affiliated SPACs and SPAC Sponsors—The Company provides office space, secretarial, administrative, and other corporate services to Atlas Crest Entities. These services are provided to the Atlas Crest Entities upon consummation of their IPOs, in each case for a fee of $10 per month. For the years ended December 31, 2021 and December 31, 2020, this fee totaled $200 and $20, respectively. This arrangement shall continue with each Atlas Crest Entity until such Atlas Crest Entity consummates a business combination or is liquidated. As of December 31, 2021 and December 31, 2020, the Company had no balances due from the Atlas Crest Entities or their sponsors.

MA Financial—As of December 31, 2021 and 2020, the Company had net balances of $0 and $5 due to MA Financial, respectively, which is reflected in accrued and other receivables on the consolidated statements of financial condition. These balances consist of amounts due to or from MA Financial for advisory services performed as well as billable expenses incurred by the Company on behalf of MA Financial during the period. The relationship between the Company and MA Financial is governed by a services agreement.

Revenues—From time to time, the Company enters into advisory transactions with affiliated entities, such as an Atlas Crest Entity or Moelis Asset Management LP and its affiliates. The Company earned revenues associated with such transactions of $30,346, $0 and $210 for the years ended December 31, 2021, 2020 and 2019, respectively.