Summary Prospectus

FlexShares^® International Quality Dividend Dynamic Index Fund

March 1, 2021 Ticker: IQDY Stock Exchange: NYSE Arca

Before you invest, you may want to review the Fund’s complete Prospectus, which contains more information about the Fund and its risks. You can find the Fund’s complete Prospectus and other information about the Fund online at www.flexshares.com/prospectus. You can also get this information at no cost by calling 1-855-FLEXETF (1-855-353-9383) or by sending an e-mail request to info@flexshares.com. The Fund’s complete Prospectus and Statement of Additional Information, both dated March 1, 2021, as supplemented, are incorporated by reference into this summary prospectus and may be obtained, free of charge, at the website, phone number or e-mail address noted above.

Investment Objective

The Fund seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Northern Trust International Quality Dividend Dynamic 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, hold and sell 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 and fees to financial intermediaries 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)
Management Fees	0.47%
Distribution (12b-1) Fees	0.00%
Other Expenses	0.01%
Total Annual Fund Operating Expenses	0.48%
Expense Reimbursement(1)	-0.01%
Total Annual Fund Operating Expenses After Expense Reimbursement	0.47%

⁽¹⁾  Northern Trust Investments, Inc. (“NTI” or the “Investment 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 0.47%. This contractual limitation may not be terminated before March 1, 2022 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.

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:

1 Year	$ 48
3 Years	$1 53
5 Years	$ 268
10 Years	$ 603

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 85% of the average value of its portfolio.

Principal Investment Strategies

The Underlying Index is designed to reflect the performance of a selection of companies that, in aggregate, possess greater financial strength and stability characteristics relative to the Northern Trust International Large Cap Index (the “Parent Index”), a float-adjusted market-capitalization weighted index of non-US domiciled large- and mid-capitalization companies. In addition, the Underlying Index is designed to select companies from the Parent Index that have enhanced risk return characteristics and that in the aggregate have the potential to generate income in excess of the income generated by securities in the Par-

 

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ent Index with a beta that is higher in relation to the Parent Index. Beta represents the market sensitivity, relative to a given market index and time period, and is one measure of volatility.

To derive the Underlying Index, Northern Trust Investments, Inc. (“NTI” or the “Investment Adviser”), acting in its capacity as the index provider (the “Index Provider”), ranks all dividend-paying constituents of the Parent Index using a Northern Trust proprietary quality factor. This factor is a quantitative ranking based on: (a) management expertise (e.g. corporate finance activities); (b) profitability (e.g. reliability and sustainability of financial performance); and (c) cash flow (e.g., cash flow generation). The Index Provider then excludes the lowest quintile of constituents ranked according to this factor and uses an optimization process to select and weight eligible securities in order to (a) maximize the overall quality score relative to the Parent Index, (b) attain an aggregate dividend yield in excess of the Parent Index and (c) target an aggregate beta 1.0 to 1.5 times that of the Parent Index. The optimization also includes sector, industry group, region, country and single-security weight constraints so that these characteristics vary within acceptable bands relative to the Parent Index. In addition to tracking the performance of the Underlying Index, the Investment Adviser seeks to minimize portfolio turnover and tax inefficiencies. As of December 31, 2020, there were 186 issues in the Underlying Index. As of December 31, 2020, the top five countries (by weighting) represented in the Underlying Index were Japan (​18.3%), Great Britain (​11.6%), China (​9.9%), France (​5.6%) and Germany (​5.2%). The Underlying Index is governed by transparent, objective rules for security selection, exclusion, rebalancing and adjustments for corporate actions.

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” its Underlying Index and does not seek temporary defensive positions when markets decline or appear overvalued.

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.

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 and in American Depositary Receipts (“ADRs”) and Global Depositary Receipts (“GDRs”) (collectively “Depositary Receipts”) based on the 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, options on futures contracts and foreign currency 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 created and sponsored by NTI, as the Index Provider. NTI also serves as the investment adviser to the Fund. 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 Index is reconstituted quarterly.

The Underlying Index of the Fund will be rebalanced or reconstituted as described above under normal market conditions. During periods of market disruption or other abnormal market conditions, the rebalancing or reconstitution of the Fund’s Underlying Index may be delayed.

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.

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.

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Equity Securities Risk is the risk that the values of the equity securities owned by the Fund may be more volatile and underperform other asset classes and the general securities markets.

Large Cap Risk is the risk that returns on investments in stocks of large companies could trail the returns on investments in stocks of smaller and mid-sized companies. In addition, larger companies may grow more slowly or be slower to respond to business developments than smaller companies.

Mid and Small Cap Stock Risk is the risk that stocks of mid-sized and smaller companies may be more volatile than stocks of larger, more established companies, and may lack sufficient market liquidity. Mid-sized and small companies may have limited product lines or financial resources, may be dependent upon a particular niche of the market, or may be dependent upon a small or inexperienced management group. Securities of smaller companies may trade less frequently and in lower volume than the securities of larger companies, which could lead to higher transaction costs. Generally the smaller the company size, the greater the risk.

Foreign Securities Risk is the risk that investing in foreign (non-U.S.) securities may result in the Fund experiencing more rapid and extreme changes in value than a fund that invests exclusively in U.S. securities, due to less liquid markets, tariffs and trade disputes and adverse economic, political, diplomatic, environmental, financial, and regulatory factors. Foreign governments also may impose limits on investment and repatriation and impose taxes. Any of these events could cause the value of the Fund’s investments to decline. To the extent that the Fund’s assets are significantly invested in a single country or geographic region, the Fund will be subject to the risks associated with that particular country or region. To the extent that the underlying securities and/or other assets held by the Fund trade on foreign exchanges or in foreign markets that may be closed when the securities exchange on which the Fund’s shares trade is open, there are likely to be deviations between the current price of such an underlying security and the last quoted price for the underlying security (i.e., the Fund’s quote from the closed foreign market). The impact of a closed foreign market on the Fund is likely to be greater where a large portion of the Fund’s underlying securities and/or other assets trade on that closed foreign market or when the foreign market is closed for unscheduled reasons. These deviations could result in premiums or discounts to the Fund’s NAV that may be greater than those experienced by other ETFs.

Emerging Markets Risk is the risk that markets of emerging market countries are less developed and less liquid, subject to greater price volatility, subject to less uniform or robust accounting, securities valuation and reporting requirements, and generally subject to increased economic, political, regulatory and other uncertainties than more developed markets.

Currency Risk is the risk that foreign currencies, securities that trade in or receive revenues in foreign currencies, or derivatives that provide exposure to foreign currencies will fluctuate in value relative to the U.S. dollar, adversely affecting the value of the Fund’s investments and its returns. Because the Fund’s NAV is determined on the basis of U.S. dollars, and the Fund does not attempt to hedge against changes in the value of non-U.S. currencies, you may lose money if the local currency of a foreign market depreciates against the U.S. dollar, even if the market value of the Fund’s holdings appreciates. In addition, fluctuations in the exchange values of currencies could affect the economy or particular business operations of companies in a geographic region in which the Fund invests, causing an adverse impact on the Fund’s investments in the affected region.

Financial Sector Risk is the risk that the Fund will be impacted by events affecting the financial sector if it invests a relatively large percentage of its assets in that sector, adversely affecting the Fund’s performance. The financial sector can be significantly affected by changes in interest rates, government regulation, the rate of corporate and consumer debt defaulted, price competitions and the availability and cost of capital funds, among other factors. The impact of changes in capital requirements and recent or future regulation of any individual financial company, or of the financials sector as a whole, cannot be predicted. In recent years, cyberattacks and technology malfunctions and failures have become increasingly frequent in this sector and have caused significant losses to companies in this sector, which may negatively impact the Fund.

Dividend Risk is the risk that an issuer of stock held by the Fund may choose not to declare a dividend or the dividend rate might not remain at current levels. Dividend paying stocks might not experience the same level of earnings growth or capital appreciation as non-dividend paying stocks. The Fund’s performance during a broad market advance could suffer because dividend paying stocks may not experience the same capital appreciation as non-dividend paying stocks.

Volatility Risk is the risk that the actual level of volatility experienced by the Fund may be greater or lower than the targeted overall volatility of the Underlying Index.

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Although the Underlying Index is designed to have a targeted overall volatility that is greater than that of the Parent Index, there is no guarantee that it will have the targeted overall volatility. The Fund will continue to seek to track the Underlying Index even if the Underlying Index does not have the targeted overall volatility. There is also the risk that the Fund may experience volatility greater or lower than that of the Underlying Index as a result of tracking error. A portfolio of securities with greater volatility is generally considered to have a higher risk profile than a portfolio with lower volatility.

Quality Factor Risk is the risk that the past performance of companies that have exhibited quality characteristics does not continue or the returns on securities issued by such companies may be less than returns from other styles of investing or the overall stock market. There may be periods when quality investing is out of favor and during which time the Fund's performance may suffer.

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, or volatility in the equity markets. Market disruptions caused by local or regional events such as war, acts of terrorism, the spread of infectious illness (including epidemics and pandemics) or other public health issues, recessions or other events or adverse investor sentiment could have a significant impact on the Fund and its investments and could result in the Fund’s shares trading at increased premiums or discounts to the Fund’s NAV. An outbreak of COVID-19, a respiratory disease caused by a novel coronavirus, has negatively affected the worldwide economy, the financial health of individual companies and the market in significant and unforeseen ways. The future impact of COVID-19 is currently unknown. The effects to public health, business and market conditions resulting from the COVID-19 pandemic may have a significant negative impact on the performance of the Fund’s investments. During periods of market disruption or other abnormal market conditions, the Fund’s exposure to the risks described elsewhere in this summary will likely increase. Market disruptions, regulatory restrictions or other abnormal market conditions could have an adverse effect on the Fund’s ability to adjust its exposure to the

required levels in order to track its Underlying Index or cause delays in the Underlying Index’s rebalancing or reconstitution schedule. During any such delay, it is possible that the Underlying Index and, in turn, the Fund will deviate from the Underlying Index’s stated methodology and therefore experience returns different than those that would have been achieved under a normal rebalancing or reconstitution schedule. Because the Fund is designed to maintain a high level of exposure to its Underlying Index at all times, it will not take any steps to invest defensively or otherwise reduce the risk of loss during market downturns.

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. As a result, whether or not the Fund invests in securities of issuers located in or with significant exposure to the countries directly affected, the value and liquidity of the Fund’s investments may be negatively affected. Securities markets may experience great short-term volatility and may fall sharply at times. Different markets may behave differently from each other and a foreign market may move in the opposite direction from the U.S. market.

Price changes may be temporary or last for extended periods. You could lose money over short periods due to fluctuation in the market prices of the Fund’s shares in response to market movements, and over longer periods during market downturns.

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 and that the Fund accepts custom baskets. 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. Tracking error risk may be higher for funds that track a foreign index, or an index that includes foreign securities,

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because regulatory and reporting requirements may differ from those in the U.S., and there is a heightened risk associated with limited availability and reliability of data used to construct the index.

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. This risk may be heightened because of its investments in non-U.S. securities.

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. A security included in an Underlying Index may not exhibit the characteristic or provide the specific exposure for which it was selected and consequently a Fund's holdings may not exhibit returns consistent with that characteristic or exposure. Unusual market conditions may cause the provider of the Underlying Index to postpone a scheduled rebalance, which could cause the Underlying Index to vary from its normal or expected composition.

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.

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 Investment 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. Among other situations, disruptions (for example, pandemics or health crises) that cause prolonged periods of remote work or significant employee absences at the Fund's service providers could impact the ability to conduct the Fund's operations. The Fund and Investment Adviser have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Investment Adviser. 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. The use of derivatives is a highly specialized activity that involves investment techniques and risks different from those associated with investments in more traditional securities and instruments.

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

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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 flexshares.com.

Calendar Year Total Returns

For the period shown in the bar chart above:

Best Quarter (12/31/2020): 22.83%

Worst Quarter (3/31/2020): -26.51%

Average Annual Total Returns

(for the periods ended December 31, 2020)

	One Year	Five Year	Since Inception of Fund	Inception Date of Fund
Before Taxes	9.36%	8.96%	5.64%	4/12/2013
After Taxes on Distributions	8.60%	7.99%	4.75%	—
After Taxes on Distributions and Sale of Shares	5.99%	6.94%	4.36%	—
MSCI ACWI ex USA Index*	10.65%	8.92%	5.71%	—
Northern Trust International Quality Dividend Dynamic IndexSM*	9.89%	9.31%	6.10%	—

*   Reflects no deduction for fees, expenses or taxes.

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.

Management

Investment Adviser and Portfolio Managers. Northern Trust Investments, Inc., a subsidiary of Northern Trust Corporation, serves as the Investment Adviser of the Fund. Robert Anstine, Brendan Sullivan and Steven Santiccoli, each a Vice President of Northern Trust Investments, Inc., have served as Portfolio Managers of the Fund since October 2013, June 2016 and March 2021, respectively.

Purchase and Sale of Fund Shares

The Fund is an exchange-traded fund (commonly referred to as an “ETF”). Individual Fund shares may only be purchased and sold in the secondary market through a broker-dealer. The price of Fund shares is based on market price, and because ETF shares trade at market prices rather than NAV, shares may trade at a price greater than NAV (a premium) or less than NAV (a discount). An investor may incur costs attributable to the difference between the high-

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est price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (“the bid-ask spread”). Recent information, including information about the Fund’s NAV, market price, premiums and discounts, and bid-ask spreads, is included on the Fund’s website at flexshares.com.

Tax Information

The Fund’s distributions are generally taxable to you as ordinary income, qualified dividends, capital gains, or a combination of the three, unless you are investing through a tax-exempt or tax-deferred arrangement, such as a 401(k) plan or an individual retirement account. Distributions may be taxable upon withdrawal from tax-deferred accounts.

Payments to Brokers-Dealers and Other Financial Intermediaries

If you purchase the Fund through a broker-dealer or other financial intermediary (such as a bank), NTI and its related companies may pay the intermediary for activities related to the marketing and promotion of the Fund. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

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