Knight Capital Group confirmed that the embattled brokerage had agreed to a $400m rescue plan that would help fill a hole left by errant trading last week.

The Jersey City-based firm told regulators in a filing Monday that the firm had entered into a "securities purchase agreement" on August 6, selling $400m worth of 2% convertible preferred stock in itself to a group of investors. Those securities will be convertible into about 267 million shares of common stock in the company. Knight currently has about 89 million shares outstanding.