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FlexShares Disciplined Duration MBS Index Fund

FlexShares® Disciplined Duration MBS Index Fund

Investment Objective

The Fund seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of The ICE BofA Merrill Lynch® Constrained Duration US Mortgage Backed Securities Index^SM (the “Underlying Index”).

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. Under the Fund’s Investment Advisory Agreement, the Fund is responsible for the following expenses: interest expenses, brokerage commissions and other trading expenses, fees and expenses of the independent trustees and their independent legal counsel, taxes and other extraordinary costs such as litigation and other expenses not incurred in the ordinary course of business. You will also incur usual and customary brokerage commissions when buying or selling shares of the Fund in the secondary market, which are not reflected in the example that follows:

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses	FlexShares Disciplined Duration MBS Index Fund FlexShares Disciplined Duration MBS Index Fund
Management Fees	0.20%
Distribution (12b-1) Fees	none
Other Expenses	0.01%
Total Annual Fund Operating Expenses	0.21%
Expense Reimbursement	(0.01%)	[1]
Total Annual Fund Operating Expenses After Expense Reimbursement	0.20%

Example

The following Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same (taking into account the expense reimbursement arrangement for one year). Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example	FlexShares Disciplined Duration MBS Index Fund FlexShares Disciplined Duration MBS Index Fund USD ($)
1 Year	$ 20
3 Years	67
5 Years	117
10 Years	$ 267

Portfolio Turnover.

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the Fund’s performance. Portfolio turnover may vary from year to year, as well as within a year. During the most recent fiscal year, the Fund’s portfolio turnover rate was 61% of the average value of its portfolio.

Principal Investment Strategies

The Underlying Index reflects the performance of a selection of investment-grade US agency residential mortgage backed pass-through securities. The term “US agency mortgage-backed pass-through security” (“MBS”) refers to a category of pass-through securities backed by pools of mortgages and issued by one of the following US government agencies: the Federal National Mortgage Association (FNMA or Fannie Mae), the Federal Home Loan Mortgage Corporation (FHLMC or Freddie Mac) or the Government National Mortgage Association (GNMA or Ginnie Mae) (each a “US Agency”). The Underlying Index is formed by grouping the universe of individual fixed-rate mortgage-backed securities pools into generic aggregates according to the following parameters: (i) agency; (ii) mortgage program; (iii) pass-through coupon; and (iv) origination year. These aggregates are then assessed based on certain criteria, as determined by ICE Data Indices, LLC as the Index Provider (“Index Provider”), to determine eligibility for inclusion in the Underlying Index. MBS that are eligible for inclusion in the Underlying Index (a) have been issued by a US Agency, (b) have a weighted average remaining time to final stated maturity of at least one year, (c) have at least $5 billion or more of outstanding face value in the coupon for a given agency program, (d) have at least $1 billion or more of outstanding face value at the time of inclusion in the Underlying Index and at least $250 million to remain in the Index and (e) are characterized by one or more of the following fixed-rate mortgage programs: 30-year, 20-year, and 15-year maturities. The Underlying Index constituents are capitalization-weighted, based on their outstanding face value times price plus accrued interest, adjusted by the Index Provider, to achieve an effective duration that is generally between 3.25 and 4.25 years. Balloon, mobile home, graduated payment and quarter coupon fixed rate mortgages are excluded from the Underlying Index, as are all collateralized mortgage obligations.

NTI uses a “passive” or indexing approach to try to achieve the Fund’s investment objective. Unlike many investment companies, the Fund does not try to “beat” the index it tracks and does not seek temporary defensive positions when markets decline or appear overvalued. In addition to tracking the performance of the Underlying Index, the Investment Adviser seeks to minimize portfolio turnover and tax inefficiencies.

NTI uses a representative sampling strategy to manage the Fund. “Representative sampling” is investing in a representative sample of securities that collectively has an investment profile similar to the Underlying Index. The Fund may or may not hold all of the securities that are included in the Underlying Index. The Fund reserves the right to invest in substantially all of the securities in its Underlying Index in approximately the same proportions (i.e., replication) if NTI determines that it is in the best interest of the Fund.

The Fund generally will invest under normal circumstances at least 80% of its total assets (exclusive of collateral held from securities lending) in the securities of the Underlying Index and in “TBA Transactions” (defined below) that represent securities in the Underlying Index. The Fund may also invest up to 20% of its assets in cash and cash equivalents, including shares of money market funds advised by NTI or its affiliates, futures contracts and options on futures contracts, as well as securities not included in the Underlying Index, but which NTI believes will help the Fund track its Underlying Index. Most transactions in mortgage pass-through securities occur through standardized contracts for future delivery in which the exact mortgage pools to be delivered are not specified until a few days prior to settlement, referred to as a “to-be announced transaction” or “TBA Transaction.” In a TBA Transaction, the buyer and seller agree upon general trade parameters such as agency, coupon rate, settlement date, par amount and price. The actual pools delivered generally are determined two days prior to the settlement date. The Fund expects to enter into such contracts on a regular basis, and pending settlement of such contracts, the Fund will invest its assets in liquid, short-term instruments, which may include shares of money market funds advised by NTI or its affiliates. The Fund will assume its pro rata share of the fees and expenses of any money market fund, in which it may invest, in addition to the Fund’s own fees and expenses.

The Underlying Index is sponsored by ICE Data Indices, LLC (the “Index Provider” or “ICE”). The Index Provider is not affiliated with the Fund or NTI. The Index Provider determines the composition and relative weightings of the securities in the Underlying Index in accordance with a published methodology and disseminates information regarding the market value of the Underlying Index. The Underlying Index is rebalanced on the last calendar day of each month. As of December 31, 2019, there were 194 MBS in the Underlying Index.

The Fund may lend securities representing up to one-third of the value of the Fund’s total assets (including the value of the collateral received).

Industry Concentration Policy. The Fund will concentrate its investments (i.e., hold 25% or more of its total assets) in a particular industry or group of industries to approximately the same extent that the Underlying Index is concentrated. For purposes of this limitation, securities of the U.S. government (including its agencies and instrumentalities) are not considered to be issued by members of any industry.

Principal Risks

As with any investment, you could lose all or part of your investment in the Fund, and the Fund’s performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund’s net asset value (“NAV”), trading price, yield, total return and ability to meet its investment objective. Each risk noted below is considered a principal risk of investing in the Fund, regardless of the order in which it appears. The significance of each risk factor below may change over time and you should review each risk factor carefully.

Mortgage-Backed Pass-Through Securities Risk is the risk of investing in mortgage-backed securities issued by a US Agency. These securities may not be backed by the full faith and credit of the U.S. government. Mortgage-backed securities are subject to Credit (or Default) Risk, Interest Rate/Maturity Risk, Debt Extension Risk and Prepayment (or Call) Risk. Because of these risks, mortgage-backed securities react differently to changes in interest rates than other bonds. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities.

U.S. Government Securities Risk is the risk that the U.S. government will not provide financial support to its agencies, instrumentalities or sponsored enterprises if it is not obligated to do so by law. Many U.S. government securities that may be purchased by the Fund are not backed by the full faith and credit of the United States. It is possible that the issuers of such securities will not have the funds to meet their payment obligations in the future.

U.S. Issuer Risk is the risk that certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund has exposure.

Income Risk is the risk that the Fund’s income may decline when interest rates fall. This decline can occur because the Fund must invest in lower-yielding bonds as bonds in its portfolio mature, bonds in the Underlying Index are substituted or the Fund otherwise needs to purchase additional bonds.

Market Risk is the risk that the value of the Fund's investments may increase or decrease in response to expected, real or perceived economic, political or financial events in the U.S. or global markets. The frequency and magnitude of such changes in value cannot be predicted. Certain securities and other investments held by the Fund may experience increased volatility, illiquidity, or other potentially adverse effects in response to changing market conditions, inflation, changes in interest rates, lack of liquidity in the bond or equity markets, volatility in the equities market or adverse investor sentiment. Market risk includes the risk that a particular style of investing, such as growth or value, may underperform the market generally. The market value of the securities in which the Fund invests may go up or down in response to the prospects of individual companies, particular sectors or governments and/or general economic conditions throughout the world due to increasingly interconnected global economies and financial markets.

Passive Investment Risk is the risk that the Fund is not actively managed and NTI does not attempt to take defensive positions in any market conditions, including declining markets.

Tracking Error Risk is the risk that the Fund’s performance may vary substantially from the performance of the Underlying Index. The Fund’s performance may vary from the performance of the Underlying Index for a number of reasons including that the Fund incurs operating expenses that the Underlying Index does not. In addition, the Fund employs a representative sampling strategy, and therefore, may incur tracking error to a greater extent than a fund that seeks to replicate an index. The representative sampling strategy used by NTI may fail to produce the intended results.

Authorized Participant Concentration Risk is the risk that the Fund may be adversely affected because it has a limited number of institutions that act as authorized participants (“Authorized Participants”). Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund and none of those Authorized Participants is obligated to engage in creation and/or redemption transactions. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined below), Fund shares may trade at a discount to NAV and possibly face trading halts and/or delisting.

Calculation Methodology Risk is the risk that the Underlying Index’s calculation methodology or sources of information may not provide an accurate assessment of included issuers or correct valuation of securities, nor is the availability or timeliness of the production of the Index guaranteed.

Market Trading Risk is the risk that the Fund faces because its shares are listed on a securities exchange, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation/redemption process of the Fund. ANY OF THESE FACTORS MAY LEAD TO THE FUND’S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

Trading in Fund shares may be halted due to market conditions or for reasons that, in the view of its listing exchange, make trading in the shares inadvisable. The market prices of Fund shares will generally fluctuate in accordance with changes in its NAV, changes in the relative supply of, and demand for, Fund shares, and changes in the liquidity, or the perceived liquidity, of the Fund’s holdings.

Concentration Risk is the risk that, to the extent the Fund’s investments are concentrated in the securities of issuers in a particular region, country, market, industry, sector or asset class, the Fund may be subject to increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that region, country, market, industry, sector or asset class.

Credit (or Default) Risk is the risk that the inability or unwillingness of an issuer or guarantor of a fixed-income security, or a counterparty to a TBA, repurchase or other transaction, to meet its payment or other financial obligations will adversely affect the value of the Fund’s investments and its returns. Changes in a debt security’s or an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on the issuer’s or counterparty’s financial condition and on the terms of the securities.

Cyber Security and Operational Risk is the risk that the Fund and its service providers may experience disruptions that arise from breaches in cyber security, human error, processing and communications errors, counterparty or third-party errors, technology or systems failures, any of which may have an adverse impact on the Fund. Failures or breaches of the electronic systems of the Fund, the Fund’s adviser, distributor, and other service providers, market makers, index providers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. The Fund and its investment adviser have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers experience cyber-attacks or other cyber-failures.

Debt Extension Risk is the risk that an issuer will exercise its right to pay principal on an obligation held by the Fund (such as a mortgage-backed security) later than expected. This may happen during a period of rising interest rates. Under these circumstances, the value of the obligation will decrease and the Fund will suffer from the inability to invest in higher yielding securities.

Derivatives Risk is the risk that derivatives may pose risks in addition to and greater than those associated with investing directly in securities, currencies and other instruments, may be illiquid or less liquid, more volatile, more difficult to value and leveraged so that small changes in the value of the underlying instrument may produce disproportionate losses to the Fund. Derivatives are also subject to counterparty risk, which is the risk that the other party to the transaction will not perform its contractual obligations.

High Portfolio Turnover Risk is the risk that active and frequent trading of the Fund’s portfolio securities may result in increased transaction costs to the Fund, including brokerage commissions, dealer mark-ups and other transaction costs, which could reduce the Fund’s return.

Interest Rate/Maturity Risk is the risk that the value of the Fund’s fixed-income assets will decline because of rising interest rates. The magnitude of this decline will often be greater for longer-term fixed-income securities than shorter-term fixed-income securities. Duration is a measure used to determine the sensitivity of a security’s price to changes in interest rates. The longer a security’s duration, the more sensitive it will be to changes in interest rates. The Fund currently faces a heightened level of interest rate risk because interest rates are at historically low levels, but are expected to increase in the future with unpredictable effects on the markets and the Fund’s investments. An increase in interest rates may cause investors to move out of fixed incomes securities on a large scale, which could adversely affect the price of fixed income securities, lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The average effective duration of the Fund’s portfolio securities may be longer or shorter than the average effective duration of the MBS of the Underlying Index. Although the Underlying Index is designed so that the average effective duration of the MBS represented in the Index generally will range between 3.25 and 4.25 years, there is no guarantee that it will do so. The Fund will continue to seek to track the Underlying Index. There is also the risk that the Fund may have a longer or shorter average effective duration than that of the MBS in the Underlying Index as a result of tracking error. A portfolio of securities with a longer average effective duration is generally considered to have a higher risk profile than a portfolio with a shorter average effective duration.

Liquidity Risk is the risk that certain portfolio securities may be less liquid than others, which may make them difficult or impossible to sell at the time and the price that the Fund would like, adversely affecting the value of the Fund’s investments and its returns. Illiquid investments may be harder to value, especially in changing markets, and if the Fund is forced to sell these investments to meet redemption requests or for other cash needs, the Fund may suffer a loss. Liquidity risk may result from the lack of an active market, reduced number and capacity of traditional market participants to make a market in fixed income securities, and may be magnified in a rising interest rate environment or other circumstances where investor redemptions from fixed income funds may be higher than normal, causing increased supply in the market due to selling activity. The market for certain investments may become illiquid under adverse market or economic conditions independent of any specific adverse changes in the conditions of a particular issuer. In such cases, the Fund, due to limitations on investments in illiquid securities and/or purchasing and selling such investments, may be unable to achieve a high degree of correlation with the Underlying Index. Additionally, in adverse market conditions, the Fund’s market price may begin to reflect illiquidity or pricing uncertainty of the Fund’s portfolio securities. This could lead to the Fund’s shares trading at a price that is higher or lower than the Fund’s net asset value. At times, such differences may be significant.

Prepayment (or Call) Risk is the risk that an issuer of a security held by the Fund may “call” or prepay the security before its stated maturity, during periods of falling interest rates, e.g., which may result in the Fund having to invest the proceeds at lower interest rates, resulting in a decline in the Fund’s income and accordingly, a decline in the Fund’s net asset value. Issuers may be more likely to prepay their securities if interest rates fall. If this happens, the Fund will not benefit from the rise in the market price of the securities that normally accompanies a decline in interest rates, and will be forced to reinvest prepayment proceeds at a time when yield on securities available in the market are lower than the yield on prepaid securities. The Fund may also lose any premium it paid to purchase the securities.

Securities Lending Risk is the risk that the Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral.

Valuation Risk is the risk that the sale price the Fund could receive for a portfolio security may differ from the Fund’s valuation of the security, particularly for securities that trade in low volume or volatile markets or that are valued using a fair value methodology. In addition, the value of the securities in the Fund’s portfolio may change on days when shareholders will not be able to purchase or sell the Fund’s shares. The Fund relies on various sources to calculate its NAV. The information may be provided by third parties that are believed to be reliable, but the information may not be accurate due to errors by such pricing sources, technological issues or otherwise.

It is possible to lose money on an investment in the Fund. An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation, any other government agency, or The Northern Trust Company, its affiliates, subsidiaries or any other bank.

Fund Performance

The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Updated information on the Fund’s performance results can be obtained by visiting www.flexshares.com.

Calendar Year Total Returns

For the period shown in the bar chart above:

Best Quarter (3/31/2019): 2.14%

Worst Quarter (12/31/2016): -1.71%

Average Annual Total Returns (for the periods ended December 31, 2019)

Average Annual Total Returns - FlexShares Disciplined Duration MBS Index Fund		One Year	Five Year	Since Inception of Fund	Inception Date of Fund
FlexShares Disciplined Duration MBS Index Fund		5.98%	1.95%	2.05%	Sep. 03, 2014
FlexShares Disciplined Duration MBS Index Fund | After Taxes on Distributions		4.51%	0.55%	0.67%
FlexShares Disciplined Duration MBS Index Fund | After Taxes on Distributions and Sale of Shares		3.52%	0.86%	0.94%
ICE BofA Merrill Lynch® Constrained Duration US Mortgage Backed Securities Index℠	[1]	6.54%	2.39%	2.51%

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement plans. After-tax returns may exceed the return before taxes due to an assumed tax benefit from realizing a capital loss on a sale of Fund shares.

[1] Northern Trust Investments, Inc. (“NTI” or the “Adviser”) has contractually agreed to reimburse a portion of the operating expenses of the Fund (other than Acquired Fund Fees and Expenses) to the extent the “Total Annual Fund Operating Expenses” exceed 0.20%. This contractual limitation may not be terminated before March 1, 2021 without the approval of the Fund’s Board of Trustees. The Fund’s Board of Trustees may terminate the contractual agreement at any time if it determines that it is in the best interest of the Fund and its shareholders.

[1] Reflects no deduction for fees, expenses or taxes.