NEW YORK — Billionaire Michael Bloomberg has narrowly won a third term as New York mayor in a race that was startlingly close.

With 96 percent of precincts reporting, Bloomberg was leading Democrat William Thompson Jr. 50.5 percent to 46.2 percent.

The richest man in New York fended off Thompson, who had tried to stoke voter resentment over the way Bloomberg changed the city’s term-limits law so he could stay in office.

Thompson won big in black and Hispanic neighborhoods. This after Bloomberg spent more than $100 million on the most expensive self-financed campaign in U.S. history.

Thompson relied on donations and matching funds for his mayoral bid and probably spent about one-tenth of Bloomberg’s total.

Bloomberg’s margin of victory was far smaller than his nearly 20-point blowout in 2005.