(Changes sourcing, adds share move)
March 15 (Reuters) - Virtu Financial Inc has made a bid to buy rival trading firm KCG Holdings Inc that could help Virtu bolster its businesses that have softened under reduced market volatility.
New York-based Virtu has proposed to acquire all the outstanding shares of KCG's common stock for $18.50-$20.00 per share in cash, valuing the company at as much as $1.33 billion.
Shares of KCG were up 27 percent in extended trading after closing at $13.73 on Wednesday. Virtu's shares were little changed.
KCG's board of directors, along with its financial and legal advisers, is reviewing the proposal, the company said.
The Wall Street Journal earlier in the day reported about the proposed deal. (http://on.wsj.com/2noyMHl) (Reporting by Nikhil Subba in Bengaluru; Editing by Maju Samuel)