Eaton Vance Series Trust II

02/27/2026 | Press release | Distributed by Public on 02/27/2026 10:34

Summary Prospectus by Investment Company (Form 497K)

Eaton Vance Income Fund of Boston

Summary Prospectus    |    March 1, 2026

Share Class and Ticker Symbols

Class A

Class C

Class I

Class R

Class R6

EVIBX

ECIBX

EIBIX

ERIBX

EIBRX

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 March 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/funddocuments, email a request to [email protected], call 1-800-262-1122, 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 Objectives

The Fund's investment objective is to provide a high level of current income. The Fund's secondary objectives are to seek growth of income and capital.

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 40 of the Fund's Prospectus and page 21  of the Fund's Statement of Additional Information.

Shareholder Fees (fees paid directly from your investment)

Class A

Class C

Class I

Class R

Class R6

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)

3.25%

None

None

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

None

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

Class R

Class R6

Management Fees

0.59%

0.59%

0.59%

0.59%

0.59%

Distribution and Service (12b-1) Fees

0.25%

1.00%

None

0.50%

None

Other Expenses

0.12%

0.12%

0.12%

0.12%

0.03%

Total Annual Fund Operating Expenses

0.96%

1.71%

0.71%

1.21%

0.62%

Eaton Vance Income Fund of Boston   | Fund Summary

Eaton Vance Income Fund of Boston (Con't)

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

$420

$621

$839

$1,465

Class C shares

$274

$539

$928

$1,821

Class I shares

$73

$227

$395

$883

Class R shares

$123

$384

$665

$1,466

Class R6

$63

$199

$346

$774

If you HELD Your Shares

1 Year

3 Years

5 Years

10 Years

Class A shares

$420

$621

$839

$1,465

Class C shares

$174

$539

$928

$1,821

Class I shares

$73

$227

$395

$883

Class R shares

$123

$384

$665

$1,466

Class R6 shares

$63

$199

$346

$774

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 48%  of the average value of its portfolio.

Principal Investment Strategies

The Fund currently invests primarily in high yield, high risk corporate bonds (commonly referred to as "junk bonds") which are rated lower than investment grade (i.e., bonds rated lower than Baa by Moody's Investors Service, Inc. ("Moody's") or lower than BBB by S&P Global Ratings ("S&P") or Fitch Ratings ("Fitch")) or are unrated and of comparable quality as determined by the investment adviser. Bonds rated BBB and Baa have speculative characteristics, while lower rated bonds are predominantly speculative.

The Fund may hold securities that are unrated or in the lowest rating categories (rated  C by Moody's or D by S&P or Fitch). Bonds rated C by Moody's are regarded as having extremely poor prospects of ever attaining any real investment standing. Bonds rated D by S&P or Fitch are in payment default or a bankruptcy petition has been filed and debt service payments are jeopardized. The Fund may utilize short sales.

The Fund invests a substantial portion of its assets in bonds issued in connection with mergers, acquisitions and other highly leveraged transactions. The Fund may invest in a wide variety of other income-producing debt instruments (including senior floating rate loans and secured and unsecured subordinated ("junior") floating rate loans, second lien loans and bridge loans) ("loans"), as well as preferred stocks and other hybrid securities that pay dividends. The Fund may invest up to 10% of its net assets in municipal obligations, including shares of affiliated investment companies which invest in municipal obligations. Some securities acquired by the Fund do not pay current income or do not make regular interest payments, while others may pay interest in the form of additional debt securities. The Fund may invest in zero coupon bonds, deferred interest bonds and bonds or preferred stocks on which the interest is payable-in-kind ("PIK"). The Fund may also invest in money market instruments. Under normal circumstances, the Fund will generally expect to hold approximately 100 securities, which may help reduce investment risk.

The Fund may invest up to 25% of total assets in foreign and emerging market securities, which are predominantly  U.S. dollar denominated. With respect to non-dollar denominated securities, the Fund may hedge currency fluctuations by entering into forward foreign currency exchange contracts.

The Fund may purchase or sell derivative instruments for hedging purposes, to seek return, to manage certain investment risks and/or as a substitute for the purchase or sale of securities. Transactions in derivative instruments may include: the purchase or sale of futures contracts on securities, indices or other financial instruments or currencies; options on futures contracts; exchange-traded and over-the-counter options on securities, indices, currencies and other instruments; interest rate, credit default, inflation and total return

2

Eaton Vance Income Fund of Boston |  Fund Summary

Eaton Vance Income Fund of Boston (Con't)

swaps; forward rate contracts and credit linked notes as well as instruments that have a greater or lesser credit risk than the security underlying that instrument. The Fund may use interest rate swaps for risk management purposes and not as a speculative investment and would typically use interest rate swaps to shorten the average interest rate re-set time of its holdings. Except as required by applicable regulation, there is no stated limit on the Fund's use of derivatives for such purposes.

The Fund's investments are actively managed and securities may be bought and sold on a daily basis. Preservation of capital is considered when consistent with the Fund's objective. The investment adviser's and sub-adviser's staff monitors the credit quality of securities held by the Fund and other securities available to the Fund. Although the investment adviser and sub-adviser consider security ratings when making investment decisions, they perform their own credit and investment analysis utilizing various methodologies including "bottom up/top down" analysis and consideration of macroeconomic and technical factors, and do not rely primarily on the ratings assigned by the rating services. The portfolio managers attempt to improve yield and preserve and enhance principal value through timely trading. The portfolio managers also consider the relative value of securities in the marketplace in making investment decisions. When deemed by the investment adviser to be relevant to its evaluation of creditworthiness and when applicable information is available, the investment adviser considers environmental, social and/or governance issues (referred to as ESG) which may impact the prospects of an issuer (or obligor) or financial performance of an obligation. When considered, one or more ESG issues are taken into account alongside other factors in the investment decision-making process and are not the sole determinant of whether an investment can be made or will remain in the Fund's portfolio.

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.

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.

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 impact of interest rate changes is significantly less for floating-rate instruments that have relatively short periodic rate resets (i.e., ninety days or less). 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 fixed income and other debt obligations, including loans (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 the event of bankruptcy of the issuer of a debt instrument, the Fund could experience delays or limitations with respect to its ability to realize the benefits of any collateral securing the instrument. 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.

3

Eaton Vance Income Fund of Boston   | Fund Summary

Eaton Vance Income Fund of Boston (Con't)

Convertible and Other Hybrid Securities Risk. Convertible and other hybrid securities (including preferred and convertible instruments) generally possess certain characteristics of both equity and debt securities. In addition to risks associated with investing in income securities, such as interest rate and credit risks, hybrid securities may be subject to issuer-specific and market risks generally applicable to equity securities. Convertible securities may also react to changes in the value of the common stock into which they convert, and are thus subject to equity investing and market risks. A convertible security may be converted at an inopportune time, which may decrease the Fund's return.

Preferred Stock Risk. Although preferred stocks represent an ownership interest in an issuer, preferred stocks generally do not have voting rights or have limited voting rights and have economic characteristics similar to fixed-income securities. Preferred stocks are subject to issuer-specific risks generally applicable to equity securities and credit and interest rate risks generally applicable to fixed-income securities. The value of preferred stock generally declines when interest rates rise and may react more significantly than bonds and other debt instruments to actual or perceived changes in the company's financial condition or prospects.

PIK Securities Risk. Bonds and preferred stocks that make payments "in-kind" ("PIK") and other securities that do not pay regular income distributions may experience greater volatility in response to interest rate changes and issuer developments. PIK securities generally carry higher interest rates compared to bonds that make cash payments of interest to reflect the increased risks associated with the deferral of interest payments. PIK securities may involve additional risk because the Fund receives no cash payments until the maturity date or a specified cash payment date. If the issuer of a PIK security defaults the Fund may lose its entire investment. The Fund may be required to sell investments to obtain cash needed for income distributions.

Derivatives Risk. The Fund's exposure to derivatives involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other investments. The use of derivatives can lead to losses because of adverse movements in the price or value of the security, instrument, index, currency, commodity, economic indicator or event underlying a derivative ("reference instrument"), due to failure of a counterparty or due to tax or regulatory constraints. Derivatives may create leverage in the Fund, which represents a non-cash exposure to the underlying reference instrument. Leverage can increase both the risk and return potential of the Fund. Derivatives risk may be more significant when derivatives are used to enhance return or as a substitute for a cash investment position, rather than solely to hedge the risk of a position held by the Fund. Use of derivatives involves the exercise of specialized skill and judgment, and a transaction may be unsuccessful in whole or in part because of market behavior or unexpected events. Changes in the value of a derivative (including one used for hedging) may not correlate perfectly with the underlying reference instrument. Derivative instruments traded in over-the-counter markets may be difficult to value, may be illiquid, and may be subject to wide swings in valuation caused by changes in the value of the underlying reference instrument. If a derivative's  counterparty is unable to honor its commitments, the value of Fund shares may decline and the Fund could experience delays in (or be unable to achieve) the return of collateral or other assets held by the counterparty. The loss on derivative transactions may substantially exceed the initial investment. A derivative investment also involves the risks relating to the reference instrument underlying the investment.

Leverage Risk. Certain Fund transactions may give rise to leverage. Leverage can result from a non-cash exposure to an underlying reference instrument. Leverage can increase both the risk and return potential of the Fund. The use of leverage may cause the Fund to maintain liquid assets or liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations. Leverage may cause the Fund's share price to be more volatile than if it had not been leveraged, as certain types of leverage may exaggerate the effect of any increase or decrease in the value of the Fund's portfolio securities. The Fund may not be able to adjust its use of leverage rapidly enough to respond to interest rate volatility, inflation, and other changing market conditions. As a result, the Fund's use of leverage may have a negative impact on the Fund's performance from time to time. The loss on leveraged investments may substantially exceed the initial investment.

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.

Short Sale Risk. The Fund will incur a loss as a result of a short sale if the price of the security sold short increases in value between the date of the short sale and the date on which the Fund purchases the security to replace the borrowed security. In addition, a lender may request, or market conditions may dictate, that securities sold short be returned to the lender on short notice, and the Fund may have to buy the securities sold short at an unfavorable price and/or may have to sell related long positions before it had intended to do so. The Fund may not be able to successfully implement its short sale strategy due to limited availability of desired securities or for other reasons. The Fund may also be required to pay a premium and other transaction costs, which would increase the cost of the security sold short. The amount of any gain will be decreased and the amount of any loss increased, by the amount of the premium, dividends, interest or expenses the Fund may be required to pay in connection with the short sale. Because losses on short sales arise from increases in the value of the security sold short, the Fund's losses are potentially unlimited in a short sale transaction. Short sales could be speculative transactions and involve special risks, including greater reliance on the investment adviser's ability to accurately anticipate the future value of a security.

4

Eaton Vance Income Fund of Boston |  Fund Summary

Eaton Vance Income Fund of Boston (Con't)

Foreign Investment Risk. Foreign investments can be adversely affected by political, economic and market developments abroad, including the imposition of economic and other sanctions by the United States or another country against a particular country or countries, organizations, entities and/or individuals. There may be less publicly available information about foreign issuers because they may not be subject to reporting practices, requirements or regulations comparable to those to which United States companies are subject. Adverse changes in investment regulations, capital requirements or exchange controls could adversely affect the value of the Fund's investments. Foreign markets may be smaller, less liquid and more volatile than the major markets in the United States and, as a result, Fund share values may be more volatile. Trading in foreign markets typically involves higher expense than trading in the United States. The Fund may have difficulties enforcing its legal or contractual rights in a foreign country.

Emerging Markets Investment Risk. Investment markets within emerging market countries are typically smaller, less liquid, less developed and more volatile than those in more developed markets like the United States, and may be focused in certain sectors. Emerging market securities often involve greater risks than developed market securities. The information available about an emerging market issuer may be less reliable than for comparable issuers in more developed capital markets.

Currency Risk. Exchange rates for currencies fluctuate daily. The value of foreign investments may be affected favorably or unfavorably by changes in currency exchange rates in relation to the  U.S. dollar. Currency markets generally are not as regulated as securities markets and currency transactions are subject to settlement, custodial and other operational risks.

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.

Zero-Coupon Bond  Risk. Zero-coupon bonds  may experience greater volatility in market value due to changes in interest rates. The Fund accrues income on the discount amortization of these investments, which it is required to distribute each year. The Fund may be required to sell investments to obtain cash needed for income distributions.

Additional Risks of Loans. Loans are traded in a private, unregulated inter-dealer or inter-bank resale market and are generally subject to contractual restrictions that must be satisfied before a loan can be bought or sold. These restrictions may impede the Fund's ability to buy or sell loans (thus affecting their liquidity) and may negatively impact the transaction price. See also "Market Risk" above. It also may take longer than seven days for transactions in loans to settle. Due to the possibility of an extended loan settlement process, the Fund may hold cash, sell investments or temporarily borrow from banks or other lenders to meet short-term liquidity needs, such as to satisfy redemption requests from Fund shareholders. The types of covenants included in loan agreements generally vary depending on market conditions, the  creditworthiness of the issuer, the nature of the collateral securing the loan and possibly other factors. Loans with fewer covenants that restrict activities of the borrower may provide the borrower with more flexibility to take actions that may be detrimental to the loan holders and provide fewer investor protections in the event of such actions or if covenants are breached. The Fund may experience relatively greater realized or unrealized losses or delays and expense in enforcing its rights with respect to loans with fewer restrictive covenants. Loans to entities located outside of the  U.S. may have substantially different lender protections and covenants as compared to loans to U.S. entities and may involve greater risks. The Fund may have difficulties and incur expense enforcing its rights with respect to non-U.S. loans and such loans could be subject to bankruptcy laws that are materially different than in the U.S. Loans may be structured such that they are not securities under securities law, and in the event of fraud or misrepresentation by a borrower, lenders may not have the protection of the anti-fraud provisions of the federal securities laws. Loans are also subject to risks associated with other types of income investments, including credit risk and risks of lower rated investments.

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.  

5

Eaton Vance Income Fund of Boston   | Fund Summary

Eaton Vance Income Fund of Boston (Con't)

Pooled Investment Vehicles Risk. Pooled investment vehicles are open- and closed-end investment companies and exchange-traded funds ("ETFs"). Pooled investment vehicles are subject to the risks of investing in the underlying securities or other investments. Shares of closed-end investment companies and ETFs may trade at a premium or discount to net asset value and are subject to secondary market trading risks. In addition, the Fund will bear a pro rata portion of the operating expenses of a pooled investment vehicle in which it invests.

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.

Focused Investment Risk. To the extent the Fund has substantial investments in a relatively small number of securities or issuers, or a particular market, industry, group of industries, country, region, group of countries, asset class or sector, the Fund's performance will be more susceptible to any single economic, market, political, or regulatory occurrence affecting those particular securities or issuers or that particular market, industry, group of industries, country, region, group of countries, assets class, or sector than a fund that invests more broadly.

General Fund Investing Risks. The Fund is not a complete investment program and there is no guarantee that the Fund will achieve its investment objectives. 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 total 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 ICE BofA U.S. High Yield Index to the Bloomberg U.S. Universal 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(es) in the table provide 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 after March 1, 2020 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.

6

Eaton Vance Income Fund of Boston |  Fund Summary

Eaton Vance Income Fund of Boston (Con't)


During the period shown in the bar chart above:

High Quarter

June 30, 2020

8.39%

Low Quarter

March 31, 2020

-12.15%

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

One Year

Five Years

Ten Years

Class A Return Before Taxes

4.75%

3.94%

5.28%

Class A Return After Taxes on Distributions

2.24%

1.72%

3.02%

Class A Return After Taxes on Distributions and Sale of Class A Shares

2.76%

2.07%

3.12%

Class C Return Before Taxes

6.37%

3.84%

4.83%

Class I Return Before Taxes

8.44%

4.90%

5.89%

Class R Return Before Taxes

7.91%

4.38%

5.35%

Class R6 Return Before Taxes

8.55%

5.00%

5.98%

Bloomberg U.S. Universal Index (reflects no deduction for fees, expenses or taxes)

7.58%

0.06%

2.43%

ICE BofA U.S. High Yield Index (reflects no deduction for fees, expenses or taxes)

8.50%

4.49%

6.44%

ICE BofA U.S. High Yield Constrained Index (reflects no deduction for fees, expenses or taxes)

8.50%

4.50%

6.43%

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.

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 BMR, 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 U.S. Universal Index, and neither shall be liable in any way to BMR, investors in the Fund or other third parties in respect of the use or accuracy of Bloomberg U.S. Universal Index  or any data included therein.  

ICE® BofA® indices are not for redistribution or other uses; provided "as is", without warranties, and with no liability.  Eaton Vance  has prepared this report and ICE Data Indices, LLC does not endorse it, or guarantee, review, or endorse Eaton Vance's products.  BofA® is a licensed registered trademark of Bank of America Corporation in the United States and other countries.  

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.

7

Eaton Vance Income Fund of Boston   | Fund Summary

Eaton Vance Income Fund of Boston (Con't)

Management

Investment Adviser. Boston Management and Research ("BMR").

Investment Sub-Adviser. Eaton Vance Advisers International Ltd. ("EVAIL").

Portfolio Managers

Name

Title

Date Began Managing Fund

Justin H. Bourgette, CFA

Managing Director of Morgan Stanley and Vice President of BMR

March 2025

Stephen C. Concannon, CFA

Managing Director of Morgan Stanley and Vice President of BMR

November 2014

Bo Hunt

Managing Director of Morgan Stanley and Vice President of BMR

March 2025

Jeffrey D. Mueller

Managing Director of Morgan Stanley and of EVAIL

June 2019

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 1-800-262-1122. The minimum initial purchase or exchange into the Fund is $1,000 for Class A, Class C and Class R, $1,000,000 for Class I and $5,000,000 for Class R6 (waived in certain circumstances). There is no minimum for subsequent investments.

Tax Information

If your shares are held in a taxable account, the Fund's distributions will be taxed to you as ordinary income and/or capital gains, unless you are exempt from taxation. If your shares are held in a tax-advantaged account, you will generally be taxed only upon withdrawals from the account.

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.

© 2026 Eaton Vance Management

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Eaton Vance Series Trust II published this content on February 27, 2026, and is solely responsible for the information contained herein. Distributed via EDGAR on February 27, 2026 at 16:34 UTC. If you believe the information included in the content is inaccurate or outdated and requires editing or removal, please contact us at [email protected]