In late morning trading, the Dow Jones industrial average was up more than 450 points, or 5.5 percent. The S&P 500, meanwhile, had advanced more than 50 points, or 5.6 percent. Overseas markets also surged.
Eight Indiana companies rose more than 10 percent, led by Irwin Financial Corp., the struggling Columbus-based bank, which increased 47 percent. Carmel-based Conseco Inc. rose 12 percent, and Indianapolis-based WellPoint Inc. rose 11 percent.
Investors appeared relieved by pledges of further coordinated actions by European and U.S. authorities to aid the crippled banking system, including plans by the Treasury to buy U.S. bank stocks.
World financial leaders now have committed a total of $3 trillion to various programs to help arrest the financial crisis.
"I'm optimistic," said Paul Coan, managing partner of locally based Wealth Planning and Management. "Because they have put so much money to work, something positive has to happen."
Based on his technical analysis of the market, Coan thinks stocks could rise 10 percent to 15 percent over the next two months before falling again in December or January.
After that, he's expecting another bull market, fueled partly by expectations that the United States will be out of recession by late next year.