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FlexShares iBoxx 5-Year Target Duration TIPS Index Fund

FlexShares® iBoxx 5-Year Target Duration TIPS Index Fund

Investment Objective

The Fund seeks to provide investment results that, before fees and expenses, correspond generally to the price and yield performance of the iBoxx 5-Year Target Duration TIPS Index (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 iBoxx 5-Year Target Duration TIPS Index Fund FlexShares iBoxx 5-Year Target Duration TIPS Index Fund
Management Fees	0.18%
Distribution (12b-1) Fees	none
Other Expenses	0.01%
Total Annual Fund Operating Expenses	0.19%
Expense Reimbursement	(0.01%)	[1]
Total Annual Fund Operating Expenses After Expense Reimbursement	0.18%

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 iBoxx 5-Year Target Duration TIPS Index Fund FlexShares iBoxx 5-Year Target Duration TIPS Index Fund USD ($)
1 Year	$ 18
3 Years	60
5 Years	106
10 Years	$ 242

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 41% of the average value of its portfolio.

Principal Investment Strategies

The Underlying Index reflects the performance of a selection of inflation protected public obligations of the U.S. Treasury, commonly known as “TIPS,” with a targeted average modified adjusted duration, as defined by IHS Markit as the Index Provider (“Index Provider”), of approximately five years. The Underlying Index includes publicly issued TIPS that have maturity dates of at least three years but not more than twenty years from an index rebalancing date. TIPS are securities issued by the U.S. Treasury that are designed to provide inflation protection to investors. TIPS’ principal and interest payments are linked to an official inflation measure (as measured by the Consumer Price Index for All Urban Consumers, or CPI-U) and the payments are supported by the full faith and credit of the United States. As of December 31, 2019, there were 23 TIPS in the Underlying Index. The components of the Underlying Index are weighted by the Index Provider to achieve the targeted average modified adjusted duration and its composition is rebalanced monthly. The Underlying Index is governed by published, objective rules for security selection, exclusion, rebalancing and adjustments, including the daily re-investment of cash flows. In addition to tracking the performance of the Underlying Index, NTI seeks to minimize portfolio turnover and tax inefficiencies.

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. NTI generally intends to replicate the constituent securities of the Fund’s Underlying Index. “Replication” is an indexing strategy in which a fund invests in substantially all of the securities in its underlying index in approximately the same proportions as in the underlying index. NTI may use a “representative sampling” strategy in certain circumstances, such as when it may not be possible or practicable to fully implement a replication strategy. Representative sampling is investing in a representative sample of securities that collectively has an investment profile similar to the Underlying Index. When the Fund uses representative sampling, it may or may not hold all of the securities that are included in the Underlying Index.

Under normal circumstances, the Fund will invest at least 80% of its total assets (exclusive of collateral held from securities lending) in the securities of 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.

The Underlying Index is sponsored by Markit Indices Limited (the “Index Provider”), an organization that is independent of the Fund and NTI. The Index Provider determines the composition and relative weightings of the securities in the Underlying Index and publishes information regarding the market value of 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).

The Fund is “non-diversified” under the Investment Company Act of 1940, as amended, and may invest more of its assets in fewer issuers than “diversified” funds.

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.

Inflation Protected Security Risk is the risk that the value of inflation protected securities, such as TIPS, generally will fluctuate in response to changes in real interest rates, generally decreasing when real interest rates rise and increasing when real interest rates fall. In addition, interest payments on inflation-protected securities will generally vary up or down along with the rate of inflation. Real interest rates are generally measured as a nominal interest less an inflation rate. As such, investors should be aware that an investment in TIPS over a particular timeframe may decrease in value even in an inflationary environment. There can be no assurance that the inflation index used will accurately measure the real rate of inflation in the prices of goods and services. Because of their inflation adjustment feature, inflation-protected bonds typically have lower yields than conventional fixed-rate bonds.

Income Risk is the risk that the Fund's income may decline due to a decline in inflation (or deflation) or due to changes in inflation expectations.

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.

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, to the extent the Fund employs a representative sampling strategy, it may incur tracking error to a greater extent than if it seeks to replicate its 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.

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.

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.

Non-Diversification Risk is the risk that Fund performance may depend on the performance of a small number of issuers because the Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers.

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 periods shown in the bar chart above:

Best Quarter (3/31/2016): 3.78%

Worst Quarter (6/30/2013): -5.17%

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

Average Annual Total Returns - FlexShares iBoxx 5-Year Target Duration TIPS Index Fund		One Year	Five Year	Since Inception of Fund	Inception Date of Fund
FlexShares iBoxx 5-Year Target Duration TIPS Index Fund		7.96%	2.58%	1.63%	Sep. 19, 2011
FlexShares iBoxx 5-Year Target Duration TIPS Index Fund | After Taxes on Distributions		7.16%	1.88%	1.09%
FlexShares iBoxx 5-Year Target Duration TIPS Index Fund | After Taxes on Distributions and Sale of Shares		4.71%	1.66%	1.01%
iBoxx 5-Year Target Duration TIPS Index	[1]	8.18%	2.64%	1.77%

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 0.18%. 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.