Feb. 10 (Bloomberg) — KKR & Co., the buyout firm run by George Roberts and Henry Kravis, will close down two funds targeting individual investors in a setback to private-equity firms' attempts to attract money from individuals and eventually the $4 trillion market for 401(k) retirement plans.

The funds, started little more than a year ago to invest in high-yield debt and distressed companies, received $33 million from investors after New York-based KKR provided them with $125 million of its own capital to get started. The funds will stop accepting new money and existing investors can sell their shares or be paid by KKR when it liquidates the pools, according to filings today with the U.S. Securities and Exchange Commission.

The decision highlights the obstacles for KKR and its largest peers as they're seeking to crack open the market for individual investors. The firms, coveted by the rich and institutional investors such as pension funds and endowments, traditionally require locking up clients' money for long periods, an option less affluent individuals aren't accustomed to. Despite the liquidations, KKR said it plans to increase offerings to smaller investors.