NEW YORK — Financial markets are soaring after investors finally got what they wanted from the European Central Bank: a concrete plan to support struggling countries in the region by buying government bonds.

The surge Thursday morning put the Standard & Poor’s 500 index back to its highest level since January 2008.

Mario Draghi, the ECB’s president, unveiled a new program to buy government bonds from the region’s struggling countries with the aim of lowering their borrowing costs. Draghi said the program will have no set limit on how much it can buy.

The S&P 500 index jumped 26 points to 1,429 shortly before noon. The Dow Jones industrial average surged 236 points to 13,282 and the Nasdaq composite index jumped 59 points to 3,129.

European markets also rose sharply.