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.
source: nytimes.com
