In corporate news, a group of bond investors calling themselves Walnut Place are challenging the $8.5 billion settlement that Bank of America reached with investors of mortgage-backed securities last week, according to a Wall Street Journal report. Bank of America's stock closed down 2.5% at $10.72. New York lender Signature Bank ( SBNY) said it would sell 4.1 million shares of common stock at $56.25 in a public offering . The bank's shares shed 1.9% to $57.43. Also Berkshire Hathaway ( BRK.A) is part of a bidding group in talks to buy Citigroup's ( C) consumer-lending business, according to a Wall Street Journal report. Citigroup's stock lost 1.5% to $41.92. Market breadth was split down the middle, while volume was light. Of 3.3 billion shares that traded on the New York Stock Exchange, 48% were rose and 49% declined. 1.6 billion shares changed hands on the Nasdaq. -- Written by Chao Deng and Melinda Peer in New York.