Simons Questioned by Investors

Investors in a hedge fund run by James Simons are asking questions about why a fund held by Mr. Simons and fund associates is racking up big gains while another held mostly by outside investors is losing money.

In a conference call Wednesday, investors asked Mr. Simons about why the Renaissance Institutional Equities Fund lost 17% this year through April, lagging behind the stock market, while another fund -- held nearly exclusively by Mr. Simons and his colleagues -- surged 12%. The fund, known as RIEF, also lost money in 2008 while the internal fund jumped 80%.