Summary Prospectus dated June 1, 2023

Parametric TABS Short-Term Municipal Bond Fund

Class / Ticker     A / EABSX     C / ECBSX     I / EIBSX

This Summary Prospectus is designed to provide investors with key fund information in a clear and concise format. Before you invest, you may want to review the Fund’s Prospectus and Statement of Additional Information, which contain more information about the Fund and its risks. The Fund’s Prospectus and Statement of Additional Information, both dated June 1, 2023, as may be amended or supplemented, are incorporated by reference into this Summary Prospectus. For free paper or electronic copies of the Fund’s Prospectus, Statement of Additional Information, annual and semi-annual shareholder reports, and other information about the Fund, go to http://www.eatonvance.com/funddocuments, email a request to contact@eatonvance.com, call 1-800-260-0761, or ask any financial advisor, bank, or broker-dealer who offers shares of the Fund. Unless otherwise noted, page number references refer to the current Prospectus for this Fund.

Investment Objective

The Fund's investment objective is to seek after-tax total return.

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. Investors may also pay commissions or other fees to their financial intermediary, which are not reflected below. You may qualify for a reduced sales charge on purchases of Class A shares if you invest, or agree to invest over a 13-month period, at least $100,000 in Eaton Vance funds. Certain financial intermediaries also may offer variations in Fund sales charges to their customers as described in Appendix A – Financial Intermediary Sales Charge Variations in the Fund's Prospectus. More information about these and other discounts is available from your financial intermediary and in Sales Charges beginning on page 26 of the Fund's Prospectus and page 22 of the Fund’s Statement of Additional Information.

Shareholder Fees (fees paid directly from your investment)	Class A	Class C	Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	3.25%	None	None
Maximum Deferred Sales Charge (Load) (as a percentage of the lower of net asset value at purchase or redemption)	None(1)	1.00%	None

⁽¹⁾ Class A shares purchased at net asset value in amounts of $500,000 or more are subject to a 0.75% contingent deferred sales charge if redeemed within 12 months of purchase.

Annual Fund Operating Expenses (expenses you pay each year as a percentage of the value of your investment)	Class A	Class C	Class I
Management Fees(1)	0.35%	0.35%	0.35%
Distribution and Service (12b-1) Fees	0.25%	1.00%	None
Other Expenses	0.11%	0.11%	0.11%
Total Annual Fund Operating Expenses	0.71%	1.46%	0.46%

⁽¹⁾ Management fees reflect a reduction pursuant to an amendment to the Fund’s investment advisory and administrative agreement effective July 1, 2022. Management Fees have been restated to reflect the fees as if the fee reduction was in effect for the Fund’s full fiscal year.

Example. This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual 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, that the operating expenses remain the same and that any expense reimbursement arrangement remains in place for the contractual period. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

	Expenses with Redemption				Expenses without Redemption
	1 Year	3 Years	5 Years	10 Years	1 Year	3 Years	5 Years	10 Years
Class A shares	$395	$545	$707	$1,179	$395	$545	$707	$1,179
Class C shares	$249	$462	$797	$1,543	$149	$462	$797	$1,543
Class I shares	$47	$148	$258	$579	$47	$148	$258	$579

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” the 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. During the most recent fiscal year, the Fund's portfolio turnover rate was 109% of the average value of its portfolio.

Principal Investment Strategies

Under normal market conditions, the Fund invests at least 80% of its net assets (plus any borrowings for investment purposes) in a diversified portfolio of municipal obligations, the interest on which is exempt from regular federal income tax (the “80% Policy”). In seeking the Fund’s investment objective, the portfolio managers emphasize tax-exempt income. The Fund normally invests in municipal obligations rated in the three highest rating categories (those rated A or higher by S&P Global Ratings (“S&P”), Fitch Ratings (“Fitch”) or Moody’s Investors Service, Inc. (“Moody’s”)) or, if unrated, determined by the investment adviser or sub-adviser to be of comparable quality at the time of purchase. The Fund may invest up to 15% of its net assets in municipal obligations rated BBB by S&P, Fitch or Moody’s or, if unrated, determined by the investment adviser or sub-adviser to be of comparable quality. The Fund will not invest more than 50% of its net assets in municipal obligations rated A at the time of purchase by S&P, Fitch or Moody’s or, if unrated, determined by the investment adviser or sub-adviser to be of comparable quality. For purposes of rating restrictions, if securities are rated differently by two or more rating agencies, the highest rating is used. The Fund may continue to hold securities that are downgraded (including bonds downgraded to below investment grade credit quality (“junk bonds”)) if the sub-adviser believes it would be advantageous to do so. The Fund will not invest in a municipal obligation the interest on which the Fund’s sub-adviser believes is subject to the federal alternative minimum tax.

With respect to its investment in municipal obligations, the Fund invests primarily in general obligation or revenue bonds. The Fund currently targets an average portfolio duration of approximately 2 - 4.5 years and an average weighted portfolio maturity of approximately 3 - 6 years, but may invest in securities of any maturity or duration, and may in the future alter its maturity or duration target range. The Fund may use various techniques to shorten or lengthen its dollar-weighted average portfolio duration, including the acquisition of municipal obligations at a premium or discount. The portfolio managers generally will seek to enhance after-tax total return by actively engaging in relative value trading within the portfolio to take advantage of price opportunities in the markets for municipal obligations and use relative value analysis to assist them in making decisions to purchase or sell investments. With respect to 20% of its net assets, the Fund may invest in municipal obligations that are not exempt from regular federal income tax, direct obligations of the U.S. Treasury and/or obligations of U.S. Government agencies, instrumentalities and government-sponsored enterprises. The Fund may hold cash and may invest in cash equivalents and money market instruments.

The sub-adviser’s process for selecting municipal obligations for purchase and sale generally includes consideration of the creditworthiness of the issuer or person obligated to repay the obligation. In evaluating creditworthiness, the sub-adviser considers ratings assigned by rating agencies and generally performs additional credit and investment analysis. The portfolio managers may also trade securities to minimize taxable capital gains to shareholders. The portfolio managers may sell a security when its credit quality declines, when the remaining maturity of a fixed-income security reaches a certain point or to pursue more attractive investment options. The portfolio managers may also consider financially material environmental, social and governance (“ESG”) factors in evaluating an issuer. These considerations may be taken into account alongside other factors in the investment selection process.

Principal Risks

Market Risk. The value of investments held by the Fund may increase or decrease in response to social, economic, political, financial, public health crises or other disruptive events (whether real, expected or perceived) in the U.S. and global markets and include events such as war, natural disasters, epidemics and pandemics, terrorism, conflicts and social unrest. These events may negatively impact broad segments of businesses and populations and may exacerbate pre-existing risks to the Fund. The frequency and magnitude of resulting changes in the value of the Fund’s investments cannot be predicted. Certain securities and other investments held by the Fund may experience increased volatility, illiquidity, or other potentially adverse effects in reaction to changing market conditions. Monetary and/or fiscal actions taken by U.S. or foreign governments to stimulate or stabilize the global economy may not be effective and could lead to high market volatility. No active trading market may exist for certain investments held by the Fund, which may impair the ability of the Fund to sell or to realize the current valuation of such investments in the event of the need to liquidate such assets.

Municipal Obligations Risk. The amount of public information available about municipal obligations is generally less than for corporate equities or bonds, meaning that the investment performance of municipal obligations may be more dependent on the analytical abilities of the investment adviser and sub-adviser than stock or corporate bond investments. The secondary market for municipal obligations also tends to be less well-developed and less liquid than many other

Parametric TABS Short-Term Municipal Bond Fund 2 Summary Prospectus dated June 1, 2023

securities markets, which may limit the Fund’s ability to sell its municipal obligations at attractive prices. The differences between the price at which an obligation can be purchased and the price at which it can be sold may widen during periods of market distress. Less liquid obligations can become more difficult to value and be subject to erratic price movements. The increased presence of non-traditional participants (such as proprietary trading desks of investment banks and hedge funds) or the absence of traditional participants (such as individuals, insurance companies, banks and life insurance companies) in the municipal markets may lead to greater volatility in the markets because non-traditional participants may trade more frequently or in greater volume.

Interest Rate Risk. In general, the value of income securities will fluctuate based on changes in interest rates. The value of these securities is likely to increase when interest rates fall and decline when interest rates rise. Duration measures the time-weighted expected cash flows of a fixed-income security, while maturity refers to the amount of time until a fixed-income security matures. Generally, securities with longer durations or maturities are more sensitive to changes in interest rates than securities with shorter durations or maturities, causing them to be more volatile. Conversely, fixed-income securities with shorter durations or maturities will be less volatile but may provide lower returns than fixed-income securities with longer durations or maturities. The Fund may own individual investments that have longer durations than the Fund's target average portfolio duration. In a rising interest rate environment, the duration of income securities that have the ability to be prepaid or called by the issuer may be extended. In a declining interest rate environment, the proceeds from prepaid or maturing instruments may have to be reinvested at a lower interest rate. Certain instruments held by the Fund pay an interest rate based on the London Interbank Offered Rate (“LIBOR”), which is the average offered rate for various maturities of short-term loans between certain major international banks. LIBOR historically has been used throughout global banking and financial industries to determine interest rates for a variety of financial instruments (such as debt instruments and derivatives) and borrowing arrangements. The ICE Benchmark Administration Limited, the administrator of LIBOR, ceased publishing certain LIBOR settings on December 31, 2021, and is expected to cease publishing the remaining LIBOR settings on June 30, 2023. Although the transition process away from LIBOR has become increasingly well defined, the impact on certain debt securities, derivatives and other financial instruments that utilize LIBOR remains uncertain. The phase-out of LIBOR may result in, among other things, increased volatility or illiquidity in markets for instruments based on LIBOR and changes in the value of such instruments.

Credit Risk. Investments in municipal obligations and other debt obligations (referred to below as “debt instruments”) are subject to the risk of non-payment of scheduled principal and interest. Changes in economic conditions or other circumstances may reduce the capacity of the party obligated to make principal and interest payments on such instruments and may lead to defaults. Such non-payments and defaults may reduce the value of Fund shares and income distributions. The value of debt instruments also may decline because of concerns about the issuer’s ability to make principal and interest payments. In addition, the credit ratings of debt instruments may be lowered if the financial condition of the party obligated to make payments with respect to such instruments deteriorates. In order to enforce its rights in the event of a default, bankruptcy or similar situation, the Fund may be required to retain legal or similar counsel, which may increase the Fund’s operating expenses and adversely affect net asset value. Municipal obligations may be insured as to principal and interest payments. If the claims-paying ability or other rating of the insurer is downgraded by a rating agency, the value of such obligations may be negatively affected.

Risks of Principal Only Investments. Principal only investments entitle the Fund to receive the stated value of such investment when held to maturity. The values of principal only investments are subject to greater fluctuation in response to changes in market interest rates than obligations that pay interest currently. The Fund will accrue income on these investments and distribute that income each year. The Fund may be required to sell other investments to obtain cash needed for such income distributions.

U.S. Government Securities Risk. Although certain U.S. Government-sponsored agencies (such as the Federal Home Loan Mortgage Corporation and the Federal National Mortgage Association) may be chartered or sponsored by acts of Congress, their securities are neither issued nor guaranteed by the U.S. Treasury. U.S. Treasury securities generally have a lower return than other obligations because of their higher credit quality and market liquidity.

Tax Risk. Income from tax-exempt municipal obligations could be declared taxable because of changes in tax laws, adverse interpretations by the relevant taxing authority or the non-compliant conduct of the issuer of an obligation.

Liquidity Risk. The Fund is exposed to liquidity risk when trading volume, lack of a market maker or trading partner, large position size, market conditions, or legal restrictions impair its ability to sell particular investments or to sell them at advantageous market prices. Consequently, the Fund may have to accept a lower price to sell an investment or continue to hold it or keep the position open, sell other investments to raise cash or abandon an investment opportunity, any of which could have a negative effect on the Fund’s performance. These effects may be exacerbated during times of financial or political stress.

Money Market Instrument Risk. Money market instruments may be adversely affected by market and economic events, such as a sharp rise in prevailing short-term interest rates; adverse developments in the banking industry, which issues or guarantees many money market instruments; adverse economic, political or other developments affecting issuers of money market instruments; changes in the credit quality of issuers; and default by a counterparty.

Parametric TABS Short-Term Municipal Bond Fund 3 Summary Prospectus dated June 1, 2023

Tax-Sensitive Investing Risk. The Fund may hold a security in order to achieve more favorable tax-treatment or sell a security in order to create tax losses. The Fund’s utilization of various tax-management techniques may be curtailed or eliminated by tax legislation, regulation or interpretations. The Fund may not be able to minimize taxable distributions to shareholders and a portion of the Fund’s distributions may be taxable.

Lower Rated Investments Risk. Investments rated below investment grade and comparable unrated investments (sometimes referred to as “junk”) have speculative characteristics because of the credit risk associated with their issuers. Changes in economic conditions or other circumstances typically have a greater effect on the ability of issuers of lower rated investments to make principal and interest payments than they do on issuers of higher rated investments. An economic downturn generally leads to a higher non-payment rate, and a lower rated investment may lose significant value before a default occurs. Lower rated investments typically are subject to greater price volatility and illiquidity than higher rated investments.

Portfolio Turnover Risk. The annual portfolio turnover rate of the Fund may exceed 100%. A mutual fund with a high turnover rate (100% or more) may generate more capital gains and may involve greater expenses (which may reduce return) than a fund with a lower rate. Capital gains distributions will be made to shareholders if offsetting capital loss carry forwards do not exist.

Risks Associated with Active Management. The success of the Fund’s investment strategy depends on portfolio management’s successful application of analytical skills and investment judgment. Active management involves subjective decisions and there is no guarantee that such decisions will produce the desired results or expected returns.

General Fund Investing Risks. The Fund is not a complete investment program and there is no guarantee that the Fund will achieve its investment objective. It is possible to lose money by investing in the Fund. The Fund is not suited for short-term trading, and investors in the Fund should be able to tolerate potentially sharp declines in value over time. Purchase and redemption activities by Fund shareholders may impact the management of the Fund and its ability to achieve its investment objective(s). In addition, the redemption by one or more large shareholders or groups of shareholders of their holdings in the Fund could have an adverse impact on the remaining shareholders in the Fund. The Fund relies on various service providers, including the investment adviser and sub-adviser, if applicable, in its operations and is susceptible to operational, information security and related events (such as public health crises, cyber or hacking attacks) that may affect the service providers or the services that they provide to the Fund. An investment in the Fund is not a deposit in a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Performance

The following bar chart and table provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and how the Fund’s average annual returns over time compare with those of two broad-based securities market indices. The returns in the bar chart are for Class A shares and do not reflect a sales charge. If the sales charge was reflected, the returns would be lower. Past performance (both before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated Fund performance information can be obtained by visiting www.eatonvance.com.

The returns in the bar chart reflect the effects of expense reductions. Absent these reductions, performance for certain periods would have been lower. Effective February 17, 2015, the Fund changed its name, objective and 80% Policy and may not have achieved the performance results shown for the period prior to February 17, 2015 under its current investment objective and strategy.

For the ten years ended December 31, 2022, the highest quarterly total return for Class A was 3.16% for the quarter ended December 31, 2022 and the lowest quarterly return was -4.72% for the quarter ended March 31, 2022. The year-to-date total return through the end of the most recent calendar quarter (December 31, 2022 to March 31, 2023) was 2.24%.

Parametric TABS Short-Term Municipal Bond Fund 4 Summary Prospectus dated June 1, 2023

Average Annual Total Return as of December 31, 2022	One Year	Five Years	Ten Years
Class A Return Before Taxes	-8.11%	0.22%	0.56%
Class A Return After Taxes on Distributions	-8.12%	0.04%	0.42%
Class A Return After Taxes on Distributions and Sale of Class A Shares	-4.30%	0.34%	0.61%
Class C Return Before Taxes	-6.70%	0.13%	0.29%
Class I Return Before Taxes	-4.76%	1.13%	1.14%
Bloomberg Municipal Managed Money 1-7 Year Bond Index  (reflects no deductions for fees, expenses or taxes)	-4.62%	1.02%	1.20%
Bloomberg 5 Year Municipal Bond Index  (reflects no deductions for fees, expenses or taxes)	-5.26%	1.23%	1.53%

These returns reflect the maximum current sales charge for Class A (3.25%) and any applicable contingent deferred sales charge (“CDSC”) for Class C. Effective November 5, 2020, Class C shares automatically convert to Class A shares eight years after purchase.  The average annual total returns listed for Class C reflect conversion to Class A shares after eight years.  Prior to November 5, 2020, Class C shares automatically converted to Class A shares ten years after purchase. Investors cannot invest directly in an Index.

After-tax returns are calculated using the highest historical individual federal income tax rates and does not reflect the impact of state and local taxes. Actual after-tax returns depend on a shareholder’s tax situation and the actual characterization of distributions, and may differ from those shown. After-tax returns are not relevant to shareholders who hold shares in tax-deferred accounts or to shares held by non-taxable entities. After-tax returns for other Classes of shares will vary from the after-tax returns presented for Class A shares. Return After Taxes on Distributions for a period may be the same as Return Before Taxes for that period because no taxable distributions were made during that period. Also, Return After Taxes on Distributions and Sale of Fund Shares for a period may be greater than or equal to Return Before Taxes and/or Return After Taxes on Distributions for the same period because of losses realized on the sale of Fund shares.

Management

Investment Adviser. Eaton Vance Management (“Eaton Vance”).

Investment Sub-Adviser. Parametric Portfolio Associates LLC (“Parametric”).

Portfolio Managers

The portfolio managers of the Fund are part of Parametric’s Tax-Advantaged Bond Strategies (“TABS”) division.

Brian C. Barney, Managing Director, Institutional Portfolio Management of Parametric, has managed the Fund since June 2010.

Devin J. Cooch, Director, Portfolio Management of Parametric, has managed the Fund since July 2013.

Alison Wagner, Portfolio Management of Parametric, has managed the Fund since June 1, 2022.

Purchase and Sale of Fund Shares

You may purchase, redeem or exchange Fund shares on any business day, which is any day the New York Stock Exchange is open for business. You may purchase, redeem or exchange Fund shares either through your financial intermediary or (except for purchases of Class C shares by accounts with no specified financial intermediary) directly from the Fund either by writing to the Fund, P.O. Box 534439, Pittsburgh, PA 15253-4439, or by calling 1-800-260-0761. The minimum initial purchase or exchange into the Fund is $1,000 for each Class (with the exception of Class I) and $1,000,000 for Class I (waived in certain circumstances). There is no minimum for subsequent investments.

Tax Information

The Fund’s distributions are expected to primarily be exempt from regular federal income tax. However, the Fund may also distribute taxable income to the extent that it invests in taxable municipal obligations or other obligations which generate taxable income. Distributions of any net realized gains are expected to be taxable.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase the Fund’s shares through a broker-dealer or other financial intermediary (such as a bank) (collectively, “financial intermediaries”), the Fund, its principal underwriter and its affiliates may pay the financial intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the financial intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

4570  6.1.23 © 2023 Eaton Vance Management

Parametric TABS Short-Term Municipal Bond Fund 5 Summary Prospectus dated June 1, 2023