GTCR Golder Rauner, one of Chicago’s biggest private equity firms, plans to raise $3 billion for its 10th buyout fund, according to a recently filed statement with the Securities and Exchange Commission.

The Chicago-based firm raised $2.8 billion for its ninth fund in 2006.

Separately,  the Teachers’ Retirement System of Illinois disclosed Monday that it has committed to invest up to $100 million in  GTCR Fund X.

Private equity was the system’s best-performing asset class in fiscal 2010, with a 19.01 percent rate of return. The portfolio has $2.99 billion of its $31.3 billion in assets  in private equity.

Since it was founded in 1980 by Stanley Golder, the firm  has invested more than $8 billion in more than 200 companies and taken nearly 40 companies public. GTCR focuses on three key areas:  financial services and  technology,  health care and information services and technology.