ARMIX Arga Emerging Markets Value Fund Institutional Shares

Item 1. Reports to Stockholders.

Mutual Funds

Nuveen Municipal Bond Funds

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Semi-Annual Report

October 31, 2012

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Table of Contents

Letter to Shareholders

Portfolio Manager’s Comments

Certain statements in this report are forward-looking statements. Discussions of specific investments are for illustration only and are not intended as recommendations of individual investments. The forward-looking statements and other views expressed herein are those of the portfolio manager as of the date of this report. Actual future results or occurrences may differ significantly from those anticipated in any forward-looking statements, and the views expressed herein are subject to change at any time, due to numerous market and other factors. The Fund disclaims any obligation to update publicly or revise any forward-looking statements or views expressed herein.

Ratings shown are the highest rating given by one of the following national rating agencies: Standard & Poor’s, Moody’s Investors Service, Inc. or Fitch, Inc. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Certain bonds backed by U.S. Government or agency securities are regarded as having an implied rating equal to the rating of such securities. Holdings designated N/R are not rated by these national rating agencies.

This Fund features portfolio management by Nuveen Asset Management, LLC, an affiliate of Nuveen Investments. Chris Drahn, CFA, has been managing the Nuveen Short Term Municipal Bond Fund since 2002.

Recently, Chris discussed the investment strategies and the Fund’s performance for the six-month period ending October 31, 2012.

How did the Fund perform during the six-month reporting period ending October 31, 2012?

The table in the Fund Performance and Expense Ratio section of this report provides total return performance information for the Fund’s Class A Shares at net asset value (NAV) for the six-month, one-year, five-year and ten-year periods ending October 31, 2012. During this period, the Fund outperformed the S&P Municipal Bond Short Index. (Prior to November 2011, the Fund’s benchmark was the Barclays 3-Year Municipal Bond Index. The Fund is now compared to the S&P Municipal Bond Short Index because it more closely reflects the Fund’s investment universe.) The Fund also surpassed the results the Lipper Short Municipal Debt Funds Classification Average.

The Fund’s outperformance relative to the S&P Index was shaped by several contributing factors. One of these was the Fund’s duration, meaning its sensitivity to changes in interest rates. Because the portfolio’s average duration was slightly longer than the benchmark, the Fund was positioned to benefit to a somewhat greater extent from the beneficial effects of falling interest rates. Rates on the market’s shortest bonds did not have much room to fall, given how low rates already were on bonds with maturities of one to three years. However, the Fund’s exposure to a handful of bonds with maturities exceeding four years enabled the Fund to capture some of the performance benefits enjoyed by these longer securities, while still maintaining an average duration squarely within the short-term universe.

The Fund’s credit rating strategy also positively benefited the Fund’s performance. Given the continued low interest rate environment, investors were willing to accept additional credit risk in exchange for added income generating potential. As a result, the Fund’s overweighting in the lower half of the investment grade bond universe, bonds with credit ratings of BBB and A, proved helpful, while its corresponding de-emphasis of AAA and AA bonds was an advantage compared with the benchmark, adding to the Fund’s returns on a relative basis.

A third contributor to our positive results was the portfolio’s sector weighting breakdown. Specifically, the Fund was overweight in several sectors that typically include a large variety of higher yielding bonds, most notably, the health care and higher education

groups. At the same time, the Fund was helpfully underweight in two sectors that failed to keep pace with the index. These were pre-refunded bonds which were at a relative performance disadvantage owing to their very high credit quality and very short maturities in an environment favoring bonds with the opposite characteristics and state general obligation (GO) bonds, another very high quality category that saw only modest appreciation during the six-month period.

While on a relative basis the Fund was generally favorably positioned, one factor that limited our upside during the reporting period was the Fund’s small exposure to cash and a few short-term securities in the portfolio. Although we sought to keep the Fund fully invested by redeploying the portfolio’s cash position in a timely manner, we nevertheless lost some investment potential by having even a small amount of cash in this very strong market for municipal securities. Similarly, the Fund’s short dated bonds generated a minimal positive return, which slightly hindered the Fund’s performance on a relative basis.

What strategies were used to manage the Fund during the six-month reporting period ended October 31, 2012?

Changes to the portfolio were relatively minor, as we focused primarily on maintaining the Fund’s favorable positioning. While managing the Fund, we are always cognizant of its role as a low volatility investment for our shareholders, and we therefore managed its duration in accordance with preserving the appropriate balance between the Fund’s total return potential and interest rate risk.

Given the healthy level of new investment inflows into the Fund, as well as the proceeds of called and maturing bonds during the period, we were regularly looking for new opportunities to invest those monies. We saw the best prospects among bonds with A and BBB credit ratings, reflecting the lower end of our investment grade bond universe, as we were able to find securities offering incremental yield at what we believed was a manageable level of credit risk. As a result of this increasing emphasis on lower investment grade rated bonds, the Fund’s allocation to AAA-rated and AA-rated issues showed a slight corresponding decline. At period end, the Fund maintained an overweighting in A-rated and BBB-rated issues while remaining underweight in AAA-rated and AA-rated securities.

Compared to the benchmark, the Fund was notably overweight in hospitals and higher education bonds, as we found good availability in these sectors and were able to take advantage of what we saw as favorable relative yields. At the same time, we remained underweight pre-refunded and state GO bonds, as we believed their very low yields made them weaker values relative to other opportunities in the marketplace.

Risk Considerations

Mutual fund investing involves risk; principal loss is possible. Debt or fixed income securities such as those held by the Fund, are subject to market risk, credit risk, interest rate risk, call risk, tax risk, political and economic risk, and income risk. As interest rates rise, bond prices fall. Credit risk refers to an issuers ability to make interest and principal payments when due. Below investment grade or high yield debt securities are subject to

liquidity risk and heightened credit risk. The Fund’s use of inverse floaters creates effective leverage. Leverage involves the risk that the Fund could lose more than its original investment and also increases the Fund’s exposure to volatility and interest rate risk.

Dividend Information

All of the Fund’s share classes experienced a decrease to their monthly dividend in September 2012.

The Fund seeks to pay dividends at a rate that reflects the past and projected performance of the Fund. To permit the Fund to maintain a more stable monthly dividend, the Fund may pay dividends at a rate that may be more or less than the amount of net investment income actually earned by the Fund during the period. If the Fund has cumulatively earned more than it has paid in dividends, it will hold the excess in reserve as undistributed net investment income (UNII) as part of the Fund’s net asset value. Conversely, if the Fund has cumulatively paid in dividends more than it has earned, the excess will constitute negative UNII that will likewise be reflected in the Fund’s net asset value. The Fund will, over time, pay all its net investment income as dividends to shareholders. As of October 31, 2012, the Fund had a positive UNII balance, based upon our best estimate, for tax purposes and a positive UNII balance for financial reporting purposes.

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Fund Performance and Expense Ratios

The Fund Performance and Expense Ratios for the Fund are shown on the following page.

Returns quoted represent past performance, which is no guarantee of future results. Current performance may be higher or lower than the performance shown. Investment returns and principal value will fluctuate so that when shares are redeemed, they may be worth more or less than their original cost. Returns without sales charges would be lower if the sales charge were included. Returns do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption of Fund shares. Income is generally exempt from regular federal income taxes. Some income may be subject to state and local income taxes and to the federal alternative minimum tax. Capital gains, if any, are subject to tax.

Returns may reflect a contractual agreement between the Fund and the investment adviser to waive certain fees and expenses; see Notes to Financial Statements, Footnote 7 — Management Fees and Other Transactions with Affiliates for more information. In addition, returns may reflect a voluntary expense limitation by the Fund’s investment adviser that may be modified or discontinued at any time without notice. For the most recent month-end performance visit www.nuveen.com or call (800) 257-8787.

Returns reflect differences in sales charges and expenses, which are primarily differences in distribution and service fees. Fund returns assume reinvestment of dividends and capital gains.

Comparative index and Lipper return information is provided for the Fund’s Class A Shares at net asset value (NAV) only.

The expense ratios shown reflect the Fund’s total operating expenses (before fee waivers and/or expense reimbursements, if any) as shown in the Fund’s most recent prospectus. The expense ratios include management fees and other fees and expenses.

Fund Performance and Expense Ratios (continued)

Nuveen Short Term Municipal Bond Fund

Refer to the first page of this Fund Performance and Expense Ratios section for further explanation of the information included within this page.

Fund Performance

Average Annual Total Returns as of October 31, 2012*

Average Annual Total Returns as of September 30, 2012 (Most Recent Calendar Quarter)*

Class A Shares have a maximum 2.50% sales charge (Offering Price). Class A Share purchases of $250,000 or more are sold at net asset value without an up-front sales charge but may be subject to a contingent deferred sales charge (CDSC), also known as a back-end sales charge, if redeemed within eighteen months of purchase. Class C Shares have a 1% CDSC for redemptions within less than twelve months, which is not reflected in the one-year total return. Class I Shares have no sales charge and may be purchased under limited circumstances or by specified classes of investors.

Yields as of October 31, 2012

Dividend Yield is the most recent dividend per share (annualized) divided by the offering price per share.

The SEC 30-Day Yield is a standardized measure of a Fund’s yield that accounts for the future amortization of premiums or discounts of bonds held in the Fund’s portfolio. The SEC 30-Day Yield is computed under an SEC standardized formula and is based on the maximum offer price per share. Dividend Yield may differ from the SEC 30-Day Yield because the Fund may be paying out more or less than it is earning and it may not include the effect of amortization of bond premium.

The Taxable-Equivalent Yield represents the yield that must be earned on a fully taxable investment in order to equal the yield of the Fund on an after-tax basis at a specified tax rate. With respect to investments that generate qualified dividend income that is taxable at a maximum rate of 15%, the Taxable-Equivalent Yield is lower.

Holding Summaries as of October 31, 2012

This data relates to the securities held in the Fund’s portfolio of investments. It should not be construed as a measure of performance for the Fund itself.

Ratings shown are the highest rating given by one of the following national rating agencies: Standard & Poor’s Group, Moody’s Investors Service, Inc. or Fitch, Inc. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Certain bonds backed by U.S. Government or agency securities are regarded as having an implied rating equal to the rating of such securities. Holdings designated N/R are not rated by these national rating agencies.

Expense Examples

As a shareholder of one or more of the Funds, you incur two types of costs: (1) transaction costs, including up-front and back-end sales charges (loads) or redemption fees, where applicable; and (2) ongoing costs, including management fees; distribution and service (12b-1) fees, where applicable; and other Fund expenses. The Examples below are intended to help you understand your ongoing costs (in dollars) of investing in the Funds and to compare these costs with the ongoing costs of investing in other mutual funds.

The Examples below are based on an investment of $1,000 invested at the beginning of the period and held through the end of the period.

The information under “Actual Performance,” together with the amount you invested, allows you to estimate actual expenses incurred over the reporting period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.60) and multiply the result by the cost shown for your share class, in the row entitled “Expenses Incurred During Period” to estimate the expenses incurred on your account during this period.

The information under “Hypothetical Performance,” provides information about hypothetical account values and hypothetical expenses based on the respective Fund’s actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund’s actual return. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expense you incurred for the period. You may use this information to compare the ongoing costs of investing in the Fund and other Funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transaction costs. Therefore, the hypothetical information is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds or share classes. In addition, if these transaction costs were included, your costs would have been higher.

For each class of the Fund, expenses are equal to the Fund’s annualized net expense ratio of .71%, 1.06% and .52% for Classes A, C and I, respectively, multiplied by the average account value over the period, multiplied by 184/365 (to reflect the one-half year period).