Knight, one of the four major market makers for the social network's high-profile offering, recorded a charge of $35.4 million, or 23 cents per share, in the second quarter for losses from the Facebook IPO.
These losses, coupled with low levels of retail trading activity at the company's core market-making segment, dragged profit down 81 percent in the quarter.
"We are evaluating all legal rights and remedies in connection with the Facebook IPO," Chief Executive Thomas Joyce said.
Knight had to compensate its clients for losses that occurred when orders originally placed at high amounts on the Nasdaq were not filled until the price had fallen below that level.
Nasdaq OMX has faced several questions over its handling of the Facebook debut on May 18, when a technical glitch caused a delay in many client orders, leading to estimated losses as high as $200 million.
"The quarter was frankly kind of a forgettable one," Joyce said on a post-earnings conference call.
Profit hit by low trading activity
Knight's second-quarter consolidated earnings fell to $3.3 million, or 4 cents per share, down from $17.6 million, or 19 cents per share, a year earlier.
Excluding a one-time investment gain in the corporate segment, it posted an adjusted loss of 3 cents.
The company, which recently acquired the futures division of Penson Financial Services, a unit of Penson Worldwide Inc, said total revenue fell 11 percent to $289.3 million.
Analysts on average were expecting the company to earn 10 cents per share on revenue of $313.6 million.
"The primary drivers of the revenue miss were weaker client activity in the institutional brokerage and also lower volume and revenue capture in market making," Stifel Nicolaus analyst Matthew Heinz said in a note.
Retail trading activity at Knight's core market-making segment was at its lowest levels since the start of the financial crisis in 2008, and the company said it continues to expect challenging market conditions in the near future.
Derivatives trader Interactive Brokers Group Inc also cited trouble at its market-making business when it reported results on Tuesday.
Shares of Knight Capital, which has a market value of $1.15 billion, were down 5 percent at $11.10 in afternoon trade on Wednesday on the New York Stock Exchange.
Interactive Brokers shares were also down 5 percent at $13.25 on the Nasdaq.
Optimistic about Europe
However, Knight was optimistic about its operations in Europe and said it was not considering pulling back any operations in the continent.
"We are not immune to the market conditions, but we have a younger business in Europe. We are still in a growth phase," CEO Joyce said, adding that the company was excited about opportunities in the futures and foreign-exchange areas.
Knight also said it will buy back shares in the current quarter. The company has about $121 million available for repurchases under its current program.
Copyright Thomson Reuters 2012
Get your daily dose of tech news, reviews, and insights, in under 80 characters on Gadgets 360 Turbo. Connect with fellow tech lovers on our Forum. Follow us on X, Facebook, WhatsApp, Threads and Google News for instant updates. Catch all the action on our YouTube channel.