The National Association of Realtors said on Monday existing home sales dropped 7.1 percent to an annual rate of 5.08 million units, the lowest level since November.

Sales have been volatile and prone to big swings up and down in recent months following the introduction in October of new mortgage regulations, which are intended to help homebuyers understand their loan options and shop around for loans best suited to their financial circumstances.

February's decline weighed on investor sentiment, with the S&P 500 stock index falling after the data was released.

Sales fell across the country, including a 17.1 percent plunge in the U.S. Northeast.

Economists had forecast home resales decreasing 2.8 percent to a pace of 5.32 million units last month. Sales were up 2.2 percent from a year ago.