Parametric TABS 1-to-10 Year Laddered Municipal Bond Fund

Summary Prospectus | June 1, 2026


Share Class and Ticker Symbols
Class A	Class C	Class I
EALBX	ECLBX	EILBX

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, 2026, 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/ppafunddocuments, email a request to contacteatonvance@morganstanley.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 provide current income exempt from regular federal income tax.

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 20 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 time of purchase or redemption)	None¹	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	0.32%	0.32%	0.32%
Distribution and Service (12b-1) Fees	0.25%	1.00%	None
Other Expenses	0.27%	0.27%	0.27%
Total Annual Fund Operating Expenses	0.84%	1.59%	0.59%
Expense Reimbursement¹	-0.19%	-0.19%	-0.19%
Total Annual Fund Operating Expenses After Expense Reimbursement	0.65%	1.40%	0.40%

The investment adviser and administrator and the sub-adviser have agreed to reimburse the Fund’s expenses to the extent that Total Annual Fund Operating Expenses exceed 0.65% for Class A shares, 1.40% for Class C shares and 0.40% for Class I shares. This expense reimbursement will continue through June 1, 2027. Any amendment to or termination of this reimbursement would require approval of the Board of Trustees. The expense reimbursement relates to ordinary operating expenses only and does not include expenses such as: brokerage commissions, acquired fund fees and expenses of unaffiliated funds, borrowing costs (including borrowing costs of any acquired funds), taxes or litigation expenses. Amounts reimbursed may be recouped by the investment adviser and administrator and sub-adviser during the same fiscal year to the extent actual expenses are less than any contractual expense cap in place during such year. Pursuant to this arrangement, the investment adviser and administrator and the sub-adviser may recoup from the Fund any reimbursed expenses during the same fiscal year if such recoupment does not cause the Fund’s Total Annual Operating Expenses after such recoupment to exceed (i) the expense limit in effect at the time of reimbursement; or (ii) the expense limit in effect at the time of recoupment.

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:


If you SOLD Your Shares
	1 Year	3 Years	5 Years	10 Years
Class A shares	$389	$566	$758	$1,311
Class C shares	$243	$483	$848	$1,672
Class I shares	$41	$170	$310	$720


If you HELD Your Shares
	1 Year	3 Years	5 Years	10 Years
Class A shares	$389	$566	$758	$1,311
Class C shares	$143	$483	$848	$1,672
Class I shares	$41	$170	$310	$720

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 63% 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 municipal obligations with final maturities of between one and ten years, the interest on which is exempt from regular federal income tax (the “80% Policy”). Municipal obligations are debt obligations issued by or on behalf of states, territories and possessions of the United States, and the District of Columbia and their political subdivisions, agencies or instrumentalities. For the purposes of the Fund’s 80% Policy, final maturity is defined as (i) the stated final maturity of a callable bond; (ii) the pre-refunded date of an existing pre-refunded bond; (iii) the earliest put date of a put bond; or (iv) the monthly re-set date of a municipal floating-rate bond or obligation. For municipal obligations held by the Fund that become pre-refunded after the Fund purchases such obligation, the final maturity of such obligation remains the stated maturity. All municipal obligations maturing within a calendar year will be defined as having the same final maturity. At least 90% of the Fund’s net assets normally is invested in municipal obligations rated at least investment grade at the time of investment (which are those rated Baa or higher by Moody’s Investors Service, Inc. (“Moody’s”), or BBB or higher by either S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”)) or, if unrated, determined by the investment adviser or sub-adviser to be of at least investment grade quality. The balance of net assets may be invested in municipal obligations rated below

investment grade and in unrated municipal obligations considered to be of comparable quality by the investment adviser or sub-adviser (“junk bonds”). For purposes of rating restrictions, if securities are rated differently by two or more rating agencies, the highest rating is used. The Fund will not invest in an obligation if the interest on that obligation is subject to the federal alternative minimum tax. 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 invests primarily in general obligation or revenue bonds. In pursuing its investment objective, the Fund seeks to weight investment in obligations such that at least 5% and not more than 15% of its net assets are invested in obligations with a final maturity in a year within the one-to-ten year maturity range (the “weighted investment strategy”). The Fund does not have a specific target for its average portfolio duration. When a municipal obligation has a final maturity of less than one year, the Fund intends to sell that security or let it mature and reinvest the proceeds in obligations with longer maturities. With respect to the Fund’s weighted investment strategy, the Fund intends to invest at least 5% of its net assets in securities with a final maturity of 10 years within 90 days of the beginning of the calendar year. The Fund’s portfolio is “laddered” by investing in municipal obligations with different final maturities so that some obligations age out of the one-to-ten year maturity range during each year.

The investment sub-adviser’s process for selecting obligations for purchase and sale emphasizes the creditworthiness of the issuer or other person obligated to repay the obligation and the relative value of the obligation in the market. In evaluating creditworthiness, the investment sub-adviser considers ratings assigned by rating agencies and generally performs additional credit and investment analysis. The portfolio managers may also trade securities to seek to minimize capital gains to shareholders. 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. Because the Fund may invest in municipal obligations, the Fund may be susceptible to political, legislative, economic, regulatory, tax or other factors affecting issuers of these municipal obligations, such as state and local governments and their agencies. To the extent that the Fund invests in municipal obligations of issuers in the same state, U.S. territory, or economic sector, it could be more sensitive to economic, business or political developments that affect such state or sector. Municipal obligations and their issuers may be more susceptible to downgrade, loss of revenue, default and bankruptcy during periods of economic stress. 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 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.

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. Because the Fund is managed toward an income objective, it may hold more longer duration or maturity obligations and thereby be more exposed to interest rate risk than municipal income funds that are managed with a greater emphasis on total return. 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.

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.

Lower Rated Investments Risk. Investments rated below investment grade and comparable unrated investments (sometimes referred to as “junk”) are speculative because of increased credit risk relative to other fixed income investments. 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.

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. Different types of U.S. government securities are subject to different levels of credit risk, including the risk of default, depending on the nature of the particular government support for that security. 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. With respect to U.S. government securities that are not backed by the full faith and credit of the United States, there is a risk that the U.S. Government will not provide financial support to such U.S. government agencies, instrumentalities or sponsored enterprises if not obligated to do so by law. U.S. Treasury and U.S. Government agency securities generally have a lower return than other obligations because of their higher credit quality and market liquidity.

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.

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.

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.

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.

Rules-Based Management Risks. The sub-adviser uses proprietary investment techniques and analyses in making investment decisions for the Fund, seeking to achieve its investment objective while minimizing exposure to security-specific risk. The strategy seeks to take advantage of certain quantitative and behavioral market characteristics identified by the sub-adviser, utilizing a rules-based process and systematic rebalancing. A systematic investment process is dependent on the sub-adviser’s skill in developing and maintaining that process. The Fund’s strategy has not been independently tested or validated, and there can be no assurance that it will achieve the desired results.

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 designed to be a long-term investment vehicle and is not suited for short-term trading. Investors in the Fund should have a long-term investment perspective and be able to tolerate potentially sharp declines in value. 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 one or more indexes intended to measure broad market performance. The Fund’s primary benchmark index was changed from the Bloomberg Short-Intermediate 1-10 Year Municipal Bond Index to the Bloomberg Municipal Bond Index effective May 1, 2024 to comply with the regulation that requires the Fund’s primary benchmark to represent the overall applicable market. The additional index in the table provides a means to compare the Fund’s average annual returns to a benchmark that the investment adviser believes is representative of the Fund’s investment universe. 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. The Fund’s performance reflects the effects of expense reductions. Absent these reductions, performance would have been lower. Updated Fund performance information can be obtained by visiting www.eatonvance.com.

During the period shown in the bar chart above:


High Quarter	December 31, 2023	6.23%
Low Quarter	March 31, 2022	-4.49%

The year-to-date total return through the end of the most recent calendar quarter (December 31, 2025 to March 31, 2026) was 0.03%.

Average Annual Total Return (for the calendar periods ended December 31, 2025)


	One Year	Five Years	Ten Years
Class A Return Before Taxes	1.88%	0.88%	1.73%
Class A Return After Taxes on Distributions	1.81%	0.81%	1.67%
Class A Return After Taxes on Distributions and Sale of Class A Shares	2.18%	1.10%	1.68%
Class C Return Before Taxes	3.48%	0.80%	1.45%
Class I Return Before Taxes	5.53%	1.80%	2.31%
Bloomberg Municipal Bond Index (reflects no deduction for fees, expenses or taxes)	4.25%	0.80%	2.34%
Bloomberg Short-Intermediate 1-10 Year Municipal Bond Index (reflects no deduction for fees, expenses or taxes)	5.01%	1.22%	1.98%

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. Class A, Class C and Class I commenced operations on May 4, 2015. Investors cannot invest directly in an Index.

BLOOMBERG® is a trademark and service mark of Bloomberg Finance L.P. and its affiliates (collectively “Bloomberg”). BARCLAYS® is a trademark and service mark of Barclays Bank Plc (collectively with its affiliates, “Barclays”), used under license. Bloomberg or Bloomberg’s licensors, including Barclays, own all proprietary rights in the Bloomberg Barclays Indices. Neither Bloomberg nor Barclays is affiliated with Eaton Vance, and neither approves, endorses, reviews or recommends the Fund. Neither Bloomberg nor

Barclays guarantees the timeliness, accurateness or completeness of any data or information relating to Bloomberg Short-Intermediate 1-10 Year Municipal Bond Index and Bloomberg Municipal Bond Index, and neither shall be liable in any way to Eaton Vance, investors in the Fund or other third parties in respect of the use or accuracy of Bloomberg Short-Intermediate 1-10 Year Municipal Bond Index and Bloomberg Municipal Bond Index or any data included therein.

After-tax returns are calculated using the highest historical individual U.S. federal income tax rates and do 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


Name	Title	Date Began Managing Fund
Brian C. Barney, CFA	Managing Director of Morgan Stanley and Managing Director, Institutional Portfolio Management of Parametric	May 2015
Devin J. Cooch, CFA	Executive Director of Morgan Stanley and Director, Portfolio Management of Parametric	June 2022
Alison Wagner, CFA	Executive Director of Morgan Stanley and Portfolio Management of Parametric	November 2021

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 U.S. 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, and a portion of the Fund’s distributions may be subject to the U.S. federal alternative minimum tax for shareholders subject to such tax. 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.