Investment funds, which include mutual funds, other regulated investment companies, and real estate investment trusts, play an increasingly important role in the U.S. economy, with financial assets of about $23 trillion in 2017. Currently, in the U.S. National Income and Product Accounts (NIPAs), statistics on investment funds are included within larger aggregate statistics but not published separately. This paper presents separate statistics on investment funds from the NIPAs, using the framework of the integrated macroeconomic accounts, or sectoral accounts. As expected, investment funds account for a significant share of total interest and dividend payments. One feature of BEA’s accounting treatment of investment funds is that they are persistent net borrowers. This paper also discusses possible alternative treatments of investment funds, currently used by the Federal Reserve Board’s Financial Accounts and the national accounts of some other countries, in which net saving and net lending are closer to zero.