By Liana B. Baker

Nov 18 (Reuters) - Business television presenter Maria Bartiromo is leaving broadcaster CNBC after 20 years to take a job at rival Fox Business Network, according to a source familiar with the matter.

CNBC President and Chief Executive Mark Hoffman announced Bartiromo's departure in a memo to employees on Monday and said she will leave the company when her contract expires on Nov. 24.

Hoffman did not say where Bartiromo was going, but a source familiar with the matter confirmed media reports that she was headed to Fox Business Network, the cable broadcaster founded six years ago by Rupert Murdoch's Twenty-First Century Fox Inc to take on CNBC, owned by Comcast Corp.

A Fox spokeswoman said she did not have any announcement to make on Bartiromo on Monday.

The Fox Business Network, launched in October 2007, become profitable in June but trails CNBC in the ratings.

Bartiromo, 46, is expected to also appear on sister network Fox News, the No. 1 cable news channel in the ratings, the source said.

Bartiromo joined CNBC in 1993 and became the first journalist to report daily live from the floor of the New York Stock Exchange. Nicknamed the "Money Honey," she was the anchor on CNBC's "Closing Bell," which aired for two hours during the week, and a half-hour show on Sundays called "On the Money."

"She has been at the center of every major financial and business news story, working hard for CNBC, since her earliest days fighting it out on the floor of the New York Stock Exchange in the mid-90s," Hoffman said in the memo obtained by Reuters.

Hoffman added that the network will use various anchors on an interim basis before it finds permanent replacements.

In 2007, Bartiromo was in the news for her ties to a senior Citigroup executive who spent $5 million of corporate funds to sponsor a show on the Sundance Channel that would include Bartiromo as a host. The executive later lost his job.

In July 2004, Bartiromo was criticized for interviewing Citigroup Chairman Sanford Weill while owning 1,000 shares of the bank's stock, which she disclosed at the beginning of the interview. CNBC later barred news staff and managers from owning individual stocks or corporate bonds.

Bartiromo has won two Emmy awards and written several books as well as columns for magazines and newspapers, including USA Today. She is married to Jonathan Steinberg, the CEO of ETF provider WisdomTree Investments and son of former corporate raider Saul Steinberg.