A Chicago-based hedge fund has taken a position in struggling subprime lender Accredited Home Lenders Holding Co. -- sending shares of the company higher.

Citadel acquired 1.1 million shares of the San Diego-based company on March 15, according to a filing with the Securities and Exchange Commission today. The shares represent 4.5 percent of the company's outstanding shares.

Late today, shares of Accredited, trading under the symbol LEND, were up $1.15 to $11.92 -- still a far cry from $60.13 on May 11, 2006.

Citadel Group, founded by billionaire Ken Griffin in 1990, provides administrative and investment-related services to a number of private investment funds and investment vehicles, according to an SEC filing. The company says it employs 1,000 people in six international offices and manages $12 billion in investment capital.