NEW YORK (Reuters) - Embattled equities trading firm Knight Capital Group was close to securing a $400 million capital injection from a group of about a half dozen investors, CNBC reported Sunday, citing a person involved with the deal.

Chicago market-maker Getco and Omaha brokerage firm TD Ameritrade appear likely to be part of the investment group, the source told CNBC.

A Knight spokesperson could not be reached by CNBC and the report did not cite any response or comment from Getco or TD Ameritrade.

The reported $400 million capital infusion would come in the form of sale of convertible securities or bonds that turn into stock in Knight at a certain fixed price, CNBC reported.

Knight has been in crisis since Wednesday, when the firm lost $440 million -- most of its capital -- after a software glitch caused it to make thousands of unintended trades.

The company said on Thursday it was actively pursuing strategic and financing alternatives.

(Reporting By Katya Wachtel; Editing by Maureen Bavdek)