Document

MIDCAP FUND



Class	A	C	J	P	Inst.	R-1	R-2	R-3	R-4	R-5	R-6
Ticker Symbol(s)	PEMGX	PMBCX	PMBJX	PMCPX	PCBIX	PMSBX	PMBNX	PMBMX	PMBSX	PMBPX	PMAQX

Principal Funds, Inc. Summary Prospectus March 1, 2017 as amended March 24, 2017

On March 13, 2017, the Board of Directors of Principal Funds, Inc. (“PFI”) approved the automatic conversion of Class P shares into Institutional Class shares. After June 22, 2017, Class P shares will no longer be available for purchase. Following the close of business on June 23, 2017, Class P shares will automatically convert into Institutional Class shares of the same Fund on the basis of the share classes’ relative net asset values on such date without the imposition of a sales charge or any other charge. At such time, delete references to Class P from this Prospectus.

Before you invest, you may want to review the Fund’s prospectus, which contains more information about the Fund and its risks. You can find the Fund’s prospectus and other information about the Fund online at www.principalfunds.com/prospectuses. You can also get this information at no cost by calling 1-800-222-5852 or by sending an email to prospectus@principalfunds.com.

This Summary prospectus incorporates by reference the Statutory Prospectus dated March 1, 2017 as supplemented March 17, 2017 and March 24, 2017, and the Statement of Additional Information dated March 1, 2017 as supplemented March 17, 2017 and March 24, 2017 (which may be obtained in the same manner as the Prospectus).


Objective:	The Fund seeks long-term growth of capital.

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 Class A Shares of Principal Funds, Inc. More information about these and other discounts is available from your financial professional and in “Choosing a Share Class and The Costs of Investing” beginning on page 417 of the Fund’s prospectus and “Multiple Class Structure” beginning on page 6 of the Fund’s Statement of Additional Information.

Shareholder Fees (fees paid directly from your investment)



	Share Class
	A	C	J	P	Inst.	R-1	R-2	R-3	R-4	R-5	R-6
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	5.50%	None	None	None	None	None	None	None	None	None	None
Maximum Deferred Sales Charge (Load) (as a percentage of the offering price or NAV when Sales Load is paid, whichever is less)	1.00%	1.00%	1.00%	None	None	None	None	None	None	None	None

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Annual Fund Operating Expenses

(expenses that you pay each year as a percentage of the value of your investment)



	Share Class
	A	C	J	P	Inst.	R-1	R-2	R-3	R-4	R-5	R-6
Management Fees	0.59%	0.59%	0.59%	0.59%	0.59%	0.59%	0.59%	0.59%	0.59%	0.59%	0.59%
Distribution and/or Service (12b-1) Fees ⁽¹⁾	0.25%	1.00%	0.15%	N/A	N/A	0.35%	0.30%	0.25%	0.10%	N/A	N/A
Other Expenses ⁽¹⁾⁽²⁾	0.15%	0.14%	0.08%	0.11%	0.09%	0.53%	0.45%	0.32%	0.28%	0.26%	176.25%
Total Annual Fund Operating Expenses	0.99%	1.73%	0.82%	0.70%	0.68%	1.47%	1.34%	1.16%	0.97%	0.85%	176.84%
Expense Reimbursement ⁽³⁾	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	(176.10)%
Total Annual Fund Operating Expenses after Expense Reimbursement	0.99%	1.73%	0.82%	0.70%	0.68%	1.47%	1.34%	1.16%	0.97%	0.85%	0.74%
⁽¹⁾ Expense information in the table has been restated to reflect current fees.
⁽²⁾ Based on estimated amounts for the current fiscal year (Class R-6).
⁽³⁾ Principal Management Corporation ("PMC"), the investment advisor, has contractually agreed to limit the Fund’s expenses by paying, if necessary, expenses normally payable by the Fund, (excluding interest expense, expenses related to fund investments, acquired fund fees and expenses, and other extraordinary expenses) to maintain a total level of operating expenses (expressed as a percent of average net assets on an annualized basis) not to exceed 0.74% for Class R-6 shares. It is expected that the expense limit will continue through the period ending February 28, 2018; however, Principal Funds, Inc. and PMC, the parties to the agreement, may mutually agree to terminate the expense limit prior to the end of the period.

Effective June 23, 2017, delete the Annual Fund Operating Expenses table and footnotes and replace with the following:

Annual Fund Operating Expenses

(expenses that you pay each year as a percentage of the value of your investment)



	Share Class
	A	C	J	Inst.	R-1	R-2	R-3	R-4	R-5	R-6
Management Fees	0.59%	0.59%	0.59%	0.59%	0.59%	0.59%	0.59%	0.59%	0.59%	0.59%
Distribution and/or Service (12b-1) Fees ⁽¹⁾	0.25%	1.00%	0.15%	N/A	0.35%	0.30%	0.25%	0.10%	N/A	N/A
Other Expenses ⁽¹⁾⁽²⁾	0.15%	0.14%	0.08%	0.09%	0.53%	0.45%	0.32%	0.28%	0.26%	176.25%
Total Annual Fund Operating Expenses	0.99%	1.73%	0.82%	0.68%	1.47%	1.34%	1.16%	0.97%	0.85%	176.84%
Expense Reimbursement ⁽³⁾⁽⁴⁾	N/A	N/A	N/A	—%	N/A	N/A	N/A	N/A	N/A	(176.23)%
Total Annual Fund Operating Expenses after Expense Reimbursement	0.99%	1.73%	0.82%	0.68%	1.47%	1.34%	1.16%	0.97%	0.85%	0.61%
⁽¹⁾ Expense information in the table has been restated to reflect current fees.
⁽²⁾ Based on estimated amounts for the current fiscal year (Class R-6).
⁽³⁾ Principal Management Corporation ("PMC"), the investment advisor, has contractually agreed to limit the Fund’s expenses by paying, if necessary, expenses normally payable by the Fund, (excluding interest expense, expenses related to fund investments, acquired fund fees and expenses, and other extraordinary expenses) to maintain "Other Expenses" (expressed as a percent of average net assets on an annualized basis) not to exceed 0.02% for Class R-6 shares. It is expected that the expense limit will continue through the period ending June 30, 2018; however, Principal Funds, Inc. and PMC, the parties to the agreement, may mutually agree to terminate the expense limit prior to the end of the period.
⁽⁴⁾ Principal Management Corporation ("PMC"), the investment advisor, has contractually agreed to limit the Fund’s expenses by paying, if necessary, expenses normally payable by the Fund, (excluding interest expense, expenses related to fund investments, acquired fund fees and expenses, and other extraordinary expenses) to maintain a total level of operating expenses (expressed as a percent of average net assets on an annualized basis) not to exceed 0.70% for Institutional Class shares. The expense cap has been added to limit the potential increase in "Other Expenses" that otherwise may occur due to an expected decrease in the number of Institutional Class shareholders of the Fund. It is expected that the expense limit will continue through the period ending June 30, 2018; however, Principal Funds, Inc. and PMC, the parties to the agreement, may mutually agree to terminate the expense limit prior to the end of the period.

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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 and that the Fund’s operating expenses remain the same. The calculation of costs takes into account any applicable contractual fee waivers and/or expense reimbursements for the period noted in the table above. Although your actual costs may be higher or lower, based on these assumptions your costs would be:



	1 year	3 years	5 years	10 years
Class A	$645	$848	$1,067	$1,696
Class C	276	545	939	2,041
Class J	184	262	455	1,014
Class P	72	224	390	871
Institutional Class	69	218	379	847
Class R-1	150	465	803	1,757
Class R-2	136	425	734	1,613
Class R-3	118	368	638	1,409
Class R-4	99	309	536	1,190
Class R-5	87	271	471	1,049
Class R-6	76	807	1,184	1,663

With respect to Classes C and J shares, you would pay the following expenses if you did not redeem your shares (all other classes would be the same as in the above example):



	1 year	3 years	5 years	10 years
Class C	$176	$545	$939	$2,041
Class J	84	262	455	1,014

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Effective June 23, 2017, delete the Example section and replace with the following:

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.



	1 year	3 years	5 years	10 years
Class A	$645	$848	$1,067	$1,696
Class C	276	545	939	2,041
Class J	184	262	455	1,014
Institutional Class	69	218	379	847
Class R-1	150	465	803	1,757
Class R-2	136	425	734	1,613
Class R-3	118	368	638	1,409
Class R-4	99	309	536	1,190
Class R-5	87	271	471	1,049
Class R-6	62	794	1,172	1,652

With respect to Classes C and J shares, you would pay the following expenses if you did not redeem your shares (all other classes would be the same as in the above example):



	1 year	3 years	5 years	10 years
Class C	$176	$545	$939	$2,041
Class J	84	262	455	1,014

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 22.4% of the average value of its portfolio.

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its net assets, plus any borrowings for investment purposes, in equity securities of companies with medium market capitalizations at the time of purchase. For this Fund, companies with medium market capitalizations are those with market capitalizations within the range of companies comprising the Russell Midcap^® Index (as of December 31, 2016, this range was between approximately $394.9 million and $57.0 billion). The Fund also invests in foreign securities.

The Fund invests in equity securities with growth and/or value characteristics. Investing in value equity securities is an investment strategy that emphasizes buying equity securities that appear to be undervalued. The growth orientation selection emphasizes buying equity securities of companies whose potential for growth of capital and earnings is expected to be above average. The Fund does not have a policy of preferring one of these categories over the other.

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Principal Risks

The value of your investment in the Fund changes with the value of the Fund's investments. Many factors affect that value, and it is possible to lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks of investing in the Fund, in alphabetical order, are:

Equity Securities Risk. The value of equity securities could decline if the issuer's financial condition declines or in response to overall market and economic conditions. A fund's principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.


•	Growth Stock Risk. If growth companies do not increase their earnings at a rate expected by investors, the market price of the stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.


•	Small and Medium Market Capitalization Companies Risk. Investments in small and medium sized companies may involve greater risk and price volatility than investments in larger, more mature companies.

•

Value Stock Risk. Value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by the fund, or the events that the portfolio manager believed would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock judged to be undervalued actually may be appropriately priced at a low level and therefore would not be profitable for the fund.

Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.

Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).

Redemption Risk. A fund that serves as an underlying fund for a fund of funds is subject to certain risks. When a fund of funds reallocates or rebalances its investments, an underlying fund may experience relatively large redemptions or investments. These transactions may cause the underlying fund to sell portfolio securities to meet such redemptions, or to invest cash from such investments, at times it would not otherwise do so, and may as a result increase transaction costs and adversely affect underlying fund performance. Moreover, a fund of fund's redemptions or reallocations among share classes of an underlying fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.

Performance

The following information provides some indication of the risks of investing in the Fund. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. You may get updated performance information by calling 1-800-222-5852 or online at:


•	For Classes A, C, J, and P - www.principalfunds.com.


•	For Institutional Class and Classes R-1, R-2, R-3, R-4, R-5, and R-6 - www.principal.com.

The bar chart shows the investment returns of the Fund’s Class A shares for each full calendar year of operations for 10 years (or, if shorter, the life of the Fund). These annual returns do not reflect sales charges on Class A shares; if they did, results would be lower. The table shows, for each share class of the Fund and for the last one, five, and ten calendar year periods (or, if shorter, the life of the Fund), how the Fund’s average annual total returns compare with those of one or more broad measures of market performance.

For periods prior to the inception date of Class C shares (January 16, 2007), Class P shares (September 27, 2010), and Class R-6 shares (November 22, 2016), the performance shown in the table for Classes C, P, and R-6 shares is based on the performance of the Fund's Class R-3 shares, adjusted to reflect the fees and expenses of each respective class. Where this adjustment for fees and expenses results in performance for a

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newer class that is higher than the historical performance of the Class R-3 shares, the historical performance of the Class R-3 shares is used for the newer class. These adjustments for these newer classes result in performance for such periods that is no higher than the historical performance of the Class R-3 shares, which were first sold on December 6, 2000.

Total Returns as of December 31 (Class A shares)



Highest return for a quarter during the period of the bar chart above:	Q2 '09	17.51	%
Lowest return for a quarter during the period of the bar chart above:	Q4 '08	(23.89	)%



Average Annual Total Returns
For the periods ended December 31, 2016	1 Year	5 Years	10 Years
Class A Return Before Taxes	3.86%	13.25%	8.92%
Class A Return After Taxes on Distributions	3.33%	12.36%	8.04%
Class A Return After Taxes on Distribution and Sale of Fund Shares	2.64%	10.57%	7.19%
Class C Return Before Taxes	8.12%	13.70%	8.69%
Class J Return Before Taxes	9.12%	14.64%	9.52%
Class P Return Before Taxes	10.22%	14.88%	9.70%
Institutional Class Return Before Taxes	10.25%	14.95%	9.98%
Class R-1 Return Before Taxes	9.38%	14.00%	9.05%
Class R-2 Return Before Taxes	9.52%	14.16%	9.19%
Class R-3 Return Before Taxes	9.70%	14.37%	9.40%
Class R-4 Return Before Taxes	9.94%	14.58%	9.60%
Class R-5 Return Before Taxes	10.02%	14.71%	9.74%
Class R-6 Return Before Taxes	9.77%	14.38%	9.40%
Russell Midcap Index (reflects no deduction for fees, expenses, or taxes)	13.80%	14.72%	7.86%

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class A shares only and would be different for the other share classes.

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Management

Investment Advisor:

Principal Management Corporation

Sub-Advisor and Portfolio Managers:

Principal Global Investors, LLC


•	K. William Nolin (since 2000), Portfolio Manager


•	Tom Rozycki (since 2013), Portfolio Manager

Purchase and Sale of Fund Shares



Share Class	Investment Type	Purchase Minimum Per Fund
A, C, and J	Initial Investment	$1,000⁽¹⁾
A, C, and J	Initial Investment for accounts with an Automatic Investment Plan (AIP)	$100
A, C, and J	Subsequent Investments	$100⁽¹⁾⁽²⁾
P, Institutional, R-1, R-2, R-3, R-4, R-5, and R-6	There are no minimum initial or subsequent investment requirements for eligible purchasers.	N/A


⁽¹⁾	Some exceptions apply; see "Purchase of Fund Shares - Minimum Investments" for more information.


⁽²⁾	For accounts with an AIP, the subsequent automatic investments must total $1,200 annually if the initial $1,000 minimum has not been met.

You may purchase or redeem shares on any business day (normally any day when the New York Stock Exchange is open for regular trading), through your plan, intermediary, or Financial Professional; by sending a written request to Principal Funds at P.O. Box 8024, Boston, MA 02266-8024 (regular mail) or 30 Dan Road, Canton, MA 02021-2809 (overnight mail); calling us at 1-800-222-5852; or accessing our website (www.principalfunds.com).

For retail investors (i.e., non-employer sponsored retirement plan investors), effective as of the close of the New York Stock Exchange on June 14, 2013 and for employer-sponsored retirement plan investors, effective as of the close of the New York Stock Exchange on August 15, 2013, the MidCap Fund will no longer be available for purchases from new investors except in limited circumstances. See the section Purchase of Fund Shares for additional information.

For retirement plan investors, effective as of the close of the New York Stock Exchange on January 31, 2017, Class R-1 and Class R-2 shares will no longer be available for purchase from new retirement plans except in limited circumstances. See Purchase of Fund Shares for additional information.

Tax Information

The Fund’s distributions you receive are generally subject to federal income tax as ordinary income or capital gain and may also be subject to state and local taxes, unless you are tax-exempt or your account is tax-deferred in which case your distributions would be taxed when withdrawn from the tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

For Class R-6 shares, the Fund and its related companies do not pay broker-dealers or other financial intermediaries (such as a bank, insurance company, investment adviser, etc.) for the sale of Fund shares or related services.

For the other share classes, if you purchase the Fund through a broker-dealer or other financial intermediary (such as a bank, insurance company, investment adviser, etc.), the Fund and its related companies may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment, or to recommend one share class of the Fund over another share class. Ask your salesperson or visit your financial intermediary's website for more information.

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