The stocks of a few small companies could be unintended victims of Galleon Group's problems.

Galleon, the hedge-fund manager whose founder, Raj Rajaratnam, was arrested Friday on charges of insider trading, recently owned 3% of the outstanding shares of OSI Pharmaceuticals Inc. (OSIP) and 5.9% of Huron Consulting Group Inc. (HURN), among other companies, according to SEC filings.

Galleon Group's equity portfolio also holds relatively small positions in many large stocks, but its stakes in some smaller companies could cause ripples in the small- and micro-cap space if the hedge-fund firm is forced to quickly sell shares.

Rajaratnam's lawyer has insisted his client isn't guilty of the charges. But investors in the group's funds could follow the lead of Rochdale Investment Management, which said Monday it was liquidating its stake in the Galleon Diversified fund. If enough investors left Galleon, managers at the firm could be forced to sell shares of companies it owns in order to meet those redemptions.

Galleon could also seek to prevent investors from redeeming money immediately.

Huron shares closed Monday up 2.5% at $24.48 while OSI shares were up 0.4% to $32.04. Galleon's OSI stake was reported as of June 30. OSI has a stock-market capitalization of about $1.9 billion, according to FactSet Research Systems Inc. Galleon's stake in Huron was reported as of mid-August. Huron, with a stock market capitalization of $524 million, provides operational and financial consulting to other companies' management teams.

In August, Huron shares plummeted to an all-time low when it announced that its dual chairman/chief executive, as well as its chief financial officer, were quitting and that the company would restate three years of financial results. The stock has more than doubled since the August announcements, but is still down almost 60% this year. Huron didn't immediately return calls seeking comment.

An OSI spokeswoman said the company is aware that Galleon owns shares in OSI, but declined further comment on anything else related to Galleon.

Galleon also owned, as of June 30, more than 6% of the outstanding shares of Hutchinson Technology Inc. (HTCH), which supplies technology for computer disk drives and has a market capitalization of less than $200 million. Hutchinson's shares closed unchanged Monday at $6.85. A company spokeswoman didn't immediately return a call seeking comment.

The biggest chunk of Galleon's U.S. holdings are very large stocks such as eBay Inc. (EBAY), Apple Inc. (AAPL) and Google Inc. (GOOG). It's unlikely that sales of these stocks by Galleon would cause much impact on their share prices. After all, Galleon's $100 million-plus position in eBay represents less than 0.5% of eBay's outstanding shares, according to filings. According to its most recent filings, Galleon also owns nominal stakes in Bank of America Corp. (BAC) and JPMorgan Chase & Co. (JPM).

The specific hedge fund managed by Rajaratnam is a technology fund.

Galleon's troubles already had an impact Monday in Sri Lanka, where Rajaratnam was born and is a citizen--he is also a citizen of the U.S. Many of Galleon's top holdings, including John Keells Holdings PLC (JKH.SL), Commercial Bank of Ceylon PLC (COMB.SL) and National Development Bank (NDB.SL), are traded on the Colombo Stock Exchange in Sri Lanka. That market's benchmark lost as much as 3% early Monday, and ended down 1.6%.

Gauging how much impact one seller could have on a stock isn't an exact science. In September and October, hedge-fund manager Eastbourne Capital Management liquidated its entire stake in Amylin Pharmaceuticals Inc. (AMLN), a company in which it owned 12.5% of outstanding shares. Amylin's stock was barely affected.

On Friday, after the arrests of Rajaratnam and five others accused in the $20 million insider-trading ring, a spokesman for Galleon said the firm was "shocked" at Rajaratnam's arrest and intends to cooperate fully, adding: "Galleon continues to operate and is highly liquid."

-By Joseph Checkler, Dow Jones Newswires; 212-416-2152; joseph.checkler@dowjones.com

(Eric Bellman and Thomas Gryta contributed to this article.)