NEW YORK - Investors dove into stocks Thursday, extending a rally that gave the Dow Jones industrial average its best four weeks since 1933.

Stocks rose across the board in heavy trading after regulators changed an accounting rule to help banks and world leaders committed to tougher oversight of financial institutions.

The Dow Jones industrials broke through 8,000 for the first time since Feb. 9 but ended slightly below that level ahead of a closely-watched monthly report on employment Friday morning that could easily upset the market if it comes in below expectations.

The Dow is now up 20.4 percent over the last month, its biggest percentage gain in a four-week period since the spring of 1933.

"Everyone is in a buying mood," said Eric Ross, director of research at brokerage Canaccord Adams. "Everyone is feeling good. … A lot of this is simply confidence."

A bad reading on jobs could easily disrupt the market's newfound sense of optimism. Economists predict the report today will show a loss of 654,000 jobs in March after a decline of 651,000 jobs in February, which was a record third straight month of job losses above 600,000. The unemployment rate is expected to rise to 8.5 percent from 8.1 percent in February.

Oil prices benefited from the better-than-expected economic news. Light, sweet crude jumped $4.25 to settle at $52.64 a barrel on the New York Mercantile Exchange.