The Knight Capital Group was an American global financial services firm engaging in market making, electronic execution, and institutional sales and trading. With its high-frequency trading algorithms Knight was the largest trader in U.S. equities, with a market share of 17.3% on NYSE and 16.9% on NASDAQ. The company agreed to be acquired by Getco LLC in December 2012 after an August 2012 trading error lost $460 million. The merger was completed in July 2013, forming KCG Holdings.