(MF Global item updated to include analyst commentary)NEW YORK ( TheStreet) -- MF Global Holdings ( MF), a foreign exchange and derivates brokerage, has hired former New Jersey Governor and Goldman Sachs ( GS) head John Corzine as its chairman and chief executive. After the announcement, MF Global's stock popped more than 11% to $7.32 in the after-hours session Tuesday. "MF Global is a firm with tremendous potential and excellent talent," Corzine said in a written statement. "I see a substantial opportunity for the firm to expand its leadership position in serving clients globally in cash and derivatives markets." Corzine's appointment is effective immediately. Current CEO Bernard Dan has resigned from MF Global for "personal reasons," the company said in its statement announcing Corzine's hiring. Also, MF's present chairman, Alison Cartwath, will retire from the board at the company's next shareholders' meeting in August. Alexander Yavorsky, an analyst at Moody's Investors Service, indicated that Corzine has his work cut out for him. In a note Tuesday afternoon, the analyst said potential concerns about the unexpected nature of the leadership change are "tempered by Mr. Corzine's decades of first-rate industry leadership." Still, Yavorksy said, MF Global remains a long way from having its problems solved. "The more important question is -- what will new management do to return MF Global to consistent, long-term profitability while keeping its risk appetite in check?" Yavorsky asked. He added that the firm's recent performance has suffered from a decline in trading volumes. Also, an "abnormally low interest rate environment" has led to increased leverage on MF's balance sheet. -Reported by Eric Rosenbaum in New York. >>See our new stock quote page. Follow TheStreet.com on Twitter and become a fan on Facebook.