Calvert U.S. Large Cap Core Responsible Index Fund

Calvert U.S. Large Cap Core Responsible Index Fund

Investment Objective

The Fund seeks to track the performance of the Calvert U.S. Large Cap Core Responsible Index (the “Index”), which measures the investment return of large-capitalization stocks.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in Calvert mutual funds. More information about these and other discounts is available from your financial professional and under “Choosing a Share Class” on page 46 and “Reduced Sales Charges” on page 48 of this Prospectus, and under “Method of Distribution” on page 23 of the Fund’s Statement of Additional Information (“SAI”).

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees - Calvert U.S. Large Cap Core Responsible Index Fund	Class A		Class C		Class Y	Class I
Maximum sales charge (load) on purchases (as a % of offering price)	4.75%		none		none	none
Maximum deferred sales charge (load) (as a % of amount purchased or redeemed, whichever is lower)	none	[1]	1.00%	[2]	none	none

Annual Fund Operating Expenses (expenses that you pay each year as a % of the value of your investment)

Annual Fund Operating Expenses - Calvert U.S. Large Cap Core Responsible Index Fund		Class A	Class C	Class Y	Class I
Management fees	[1]	0.27%	0.27%	0.27%	0.27%
Distribution and service (12b-1) fees		0.25%	1.00%	none	none
Other expenses		0.22%	0.27%	0.32%	0.11%
Total annual fund operating expenses		0.74%	1.54%	0.59%	0.38%
Less fee waiver and/or expense reimbursement	[2]	(0.20%)	(0.25%)	(0.30%)	(0.19%)
Total annual fund operating expenses after fee waiver and/or expense reimbursement		0.54%	1.29%	0.29%	0.19%

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 ($100,000 in the case of Class I shares) in the Fund for the time periods indicated and then either redeem or hold your shares at the end of those periods;

• your investment has a 5% return each year;

• the Fund’s operating expenses remain the same; and  

• any expense limitation is in effect for the period indicated in the fee table above.

Although your actual costs may be higher or lower, under these assumptions your costs would be:

Expense Example - Calvert U.S. Large Cap Core Responsible Index Fund - USD ($)	1 Year	3 Years	5 Years	10 Years
Class A	528	681	848	1,332
Class C	231	462	816	1,813
Class Y	30	159	299	709
Class I	195	1,007	1,920	4,597

Expense Example, No Redemption - Calvert U.S. Large Cap Core Responsible Index Fund - USD ($)	1 Year	3 Years	5 Years	10 Years
Class A	528	681	848	1,332
Class C	131	462	816	1,813
Class Y	30	159	299	709
Class I	195	1,007	1,920	4,597

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (“turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the “Example”, affect the Fund’s performance. During the fiscal year ended September 30, 2015, the Fund’s portfolio turnover rate was 33% of its portfolio’s average value.

Principal Investment Strategies

The Fund employs a passive management strategy designed to track, as closely as possible, the performance of the Index. The Fund uses a replication index method, investing in the common stock of each company in the Index in about the same proportion as represented in the Index itself. The Fund will normally invest at least 95% of its net assets, including borrowings for investment purposes, in securities contained in the Index. The Fund will provide shareholders with at least 60 days’ notice before changing this policy.

Calvert U.S. Large Cap Core Responsible Index.  The Index is composed of companies that operate their businesses in a manner that is consistent with the Calvert Principles for Responsible Investment (the “Calvert Principles”) and are selected from the universe of companies included in the S-Network U.S. Equity Large Cap 1000 Index. The S-Network U.S. Equity Large Cap 1000 Index is a capitalization-weighted, float-adjusted equity index designed to serve as an equity benchmark for large cap stocks that are traded in the U.S. markets. As of November 30, 2016, the Index included 699 companies, and the market capitalization ranged from $935.2 million to $589.7 billion with a weighted average market capitalization of $127.6 billion. The number of companies in the Index will change over time due to company mergers or changes resulting from CRM’s evaluation of an issuer’s conduct relative to the Calvert Principles. The Index is reconstituted semi-annually and is rebalanced quarterly.

Indexing. An index is a group of securities whose overall performance is used as a standard to measure investment performance. An index (or “passively managed”) fund tries to match, as closely as possible, the performance of an established target index. An index fund’s goal is to mirror the target index whether the index is going up or down. Therefore, index funds do not need the costly research and analysis employed by active fundamental asset managers. To track its target index as closely as possible, the Fund attempts to remain fully invested in stocks. To help stay fully invested, and to reduce transaction costs, the Fund may invest to a limited extent in stock futures contracts, or other registered investment companies.

The Fund uses a replication method of indexing. If assets should ever decline to below $5 million, it may use the sampling method. The replication method involves holding every security in the Index in about the same proportion as the Index. The sampling method involves selecting a representative number of securities that will resemble the Index in terms of key risk and other characteristics.

Although index funds by their nature tend to be tax-efficient investment vehicles, the Fund generally is managed without regard to tax ramifications.

Responsible Investing. The Calvert Principles for Responsible Investment serve as a framework for considering environmental, social and governance factors that may affect investment performance.

Principal Risks

Index Tracking Risk. An index fund has operating expenses; a market index does not. Although expected to track its target index as closely as possible it will not be able to match the performance of the index exactly.

Stock Market Risk. The market prices of stocks held by the Fund may fall.

Common Stock Risk. Although common stocks have a history of long-term growth in value, their prices fluctuate based on changes in a company’s financial condition, on overall market and economic conditions, and on investors’ perception of a company’s well-being.

Large-Cap Company Risk. Large-cap companies may be unable to respond quickly to new competitive challenges such as changes in technology, and also may not be able to attain the high growth rate of successful smaller companies, especially during extended periods of economic expansion.

Mid-Cap Company Risk. Prices of mid-cap stocks can be more volatile than those of larger, more established companies. Mid-cap companies are more likely to have more limited product lines, fewer capital resources and less depth of management than larger companies.

Futures Contracts Risk. The value of a futures contract tends to increase and decrease in tandem with the value of the underlying instrument. The price of futures can be highly volatile; using them could lower total return, and the potential loss from futures can exceed the Fund’s initial investment in such contracts. Futures contracts may not provide an effective hedge of the underlying securities or indexes because changes in the prices of futures contracts may not track those of the securities or indexes that they are intended to hedge.

Investments in Other Investment Companies. The risks of investing in other investment companies typically reflect the risks of the types of securities in which those investment companies invest. When the Fund invests in another investment company, shareholders of the Fund bear their proportionate share of the other investment company’s fees and expenses as well as their share of the Fund’s fees and expenses.

Responsible Investing Risk.  Investing primarily in responsible investments carries the risk that, under certain market conditions, the Fund may underperform funds that do not utilize a responsible investment strategy.  The application of responsible investment criteria may affect the Fund’s exposure to certain sectors or types of investments, and may impact the Fund’s relative investment performance depending on whether such sectors or investments are in or out of favor in the market.  An investment’s ESG performance, or the Adviser’s assessment of such performance, may change over time, which could cause the Fund to temporarily hold investments that do not comply with the Fund’s responsible investment criteria.  In evaluating an investment, the Adviser is dependent upon information and data that may be incomplete, inaccurate or unavailable, which could cause the Adviser to misanalyze the ESG factors relevant to a particular investment.  Successful application of the Fund’s responsible investment strategy will depend on the Adviser’s skill in properly identifying and analyzing material ESG issues.

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. An investment in the Fund is not a deposit in a bank and is not insured.

Performance

The following bar chart and table show the Fund’s annual returns and its long-term performance, which give some indication of the risks of investing in the Fund. The bar chart shows how the performance of the Class A shares has varied from year to year. The table compares the Fund’s performance over time with that of two securities market benchmark indices. The performance reflected in the bar chart and table assumes the reinvestment of dividends and capital gains distributions, if any.

The Fund’s past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. For updated performance information, visit www.calvert.com.

The return for each of the Fund’s other Classes of shares will differ from the Class A returns shown in the bar chart, depending upon the expenses of that Class. The bar chart does not reflect any sales charge that you may be required to pay upon purchase or redemption of the Fund’s shares. Any sales charge will reduce your return.

For the ten years ended December 31, 2015, the highest quarterly total return for Class A was 18.19% for the quarter ended June 30, 2009 and the lowest quarterly return was -25.52% for the quarter ended December 31, 2008.

Average Annual Total Returns as of December 31, 2015

Average Annual Total Returns - Calvert U.S. Large Cap Core Responsible Index Fund	One Year	Five Years	Ten Years	Inception Date
Class A	(4.05%)	11.30%	5.92%
Class A | After Taxes on Distributions	(5.85%)	10.52%	5.47%
Class A | After Taxes on Distributions and Sales	(1.27%)	8.97%	4.73%
Class C	(1.02%)	11.40%	5.44%
Class Y	0.92%	12.44%	6.46%	Jul. 13, 2012
Class I	1.14%	12.97%	7.00%
Calvert U.S. Large Cap Core Responsible Index (reflects no deduction for fees, expenses or taxes)	1.44%	13.31%	7.49%
Russell 1000 Index	0.92%	12.44%	7.40%

These returns reflect the maximum sales charge for Class A (4.75%) and any applicable contingent deferred sales charge (“CDSC”) for Class C.  Performance results for Class Y shares prior to July 13, 2012 (the Class Y shares’ inception date) reflect the performance of Class A shares at net asset value. Actual Class Y share performance would have been higher than Class A share performance because Class Y has lower class-specific expenses than Class A.  Investors cannot invest directly in an Index.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Actual after-tax returns depend on your tax situation and may differ from those shown. The after-tax returns shown are not relevant to you if you hold your Fund shares through a tax-deferred arrangement such as a 401(k) plan or individual retirement account. The return after taxes on distributions and sale of Fund shares may be higher than the return before taxes because the calculation assumes that shareholders receive a tax benefit for capital losses incurred on the sale of their shares. After-tax returns are shown only for Class A shares; after-tax returns for other Classes will vary.

[1] Purchases of Class A shares at net asset value for accounts with $1,000,000 or more which a finder's fee has been paid are subject to a one-year contingent deferred sales charge of 0.25%.

[2] Applies to redemptions of Class C shares within one year of purchase.

[1] Management fees are restated to reflect current contractual fees rather than the fees paid during the previous fiscal year.

[2] Calvert Research and Management ("CRM") has agreed to reimburse the Fund's expenses to the extent that Total Annual Fund Operating Expenses exceed 0.54% for Class A, 1.29% for Class C, 0.29% for Class Y and 0.19% for Class I. This expense reimbursement will continue through January 31, 2018. Any amendment to or termination of this reimbursement would require approval of the Board of Directors. 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, interest expense, taxes or litigation expenses. Amounts reimbursed may be recouped by CRM during the same fiscal year to the extent actual expenses are less than the contractual expense cap during such year. The contractual administrative fee is 0.12%. CRM has agreed to contractually waive 0.02% of the administrative fee on Class I shares through January 31, 2018.