NEW YORK (Reuters) - Knight Capital Group <KCG.N> agreed to sell itself to Getco Holding Company LLC, beating rival high-speed trading firm Virtu Financial LLC, according to two people close to the negotiations.

Though Virtu had offered an all-cash deal, Getco and its private equity firm General Atlantic increased its offer to above $3.60 a share in cash and stock in the combined company, one source said. Under Getco's plan, Knight Chief Executive Thomas Joyce would give up his role.

A spokeswoman at Knight was not immediately available for comment.

(Reporting by Jed Horowitz; Editing by Jan Paschal)

(This Dec. 18 story was corrected to remove Exclusive tag from headline and slug. Dow Jones reported the news earlier)