Carlyle Group LP plans to price its IPO between $22 and $23 per unit, lower than its initial $23 to $25 range, a source familiar with the matter said on Wednesday, as the private equity firm courts stock market investors.

The book has closed, and orders have been received within the new price range for more than the 30.5 million shares on offer, the source said. Pricing of the initial public offering is expected after the market close on Wednesday, with trading starting on Thursday on Nasdaq under the ticker symbol "CG" .

A Carlyle spokesman declined to comment.

Carlyle has sought to position itself as different from other private equity firms like Blackstone Group LP and Apollo Global Management LLC, whose shares have sunk following their IPOs.

Blackstone shares have tumbled 56 percent since the company's 2007 IPO, while Apollo has declined 32 percent. Oaktree Capital Group LLC, which went public in April, has fallen 6 percent.

"Private equity firms have not been performing that well as they're getting pressure from all sides," said Reena Aggarwal, a professor of business administration and finance at Georgetown University's McDonough School of Business in Washington. "Fundraising has become somewhat of an issue; they are getting pressure on the fee structure from limited partners."

Carlyle also tried to price its IPO more conservatively than peers, according to people familiar with the deal. Under the new price range, the firm would raise between $671 million and $701.5 million and would be valued at up to $7 billion. This would value Carlyle at less than half of Blackstone.

Carlyle, which has about $147 billion in assets under management, returned a record $19 billion to its fund investors in 2011 and reported a 152 percent year-on-year jump in distributable earnings, as sales of several assets in its funds boosted profits.

J.P. Morgan, Citigroup, Credit Suisse and Bank of America Merrill Lynch are among the underwriters of the IPO.