NEW YORK — Financial markets grew more upbeat Thursday as political leaders said they struck an agreement in principle on a massive spending plan to revive the crippled financial system. The Dow Jones industrial average jumped about 200 points on optimism about the bailout, and demand for safe-haven assets remained high but eased slightly as some investors placed bets that a deal would help unclog credit markets.

Still, some investors had their doubts. Demand eased but remained high for the 3-month Treasury bill, considered the safest short-term investment. Its yield rose to 0.75 percent from 0.49 percent late Wednesday. That means investors are still willing to earn the slimmest of returns in exchange for a safe place to put their money. The yield on the benchmark 10-year Treasury note, which moves opposite its price, rose to 3.84 percent from 3.81 late Wednesday.

The Dow rose 196.89, or 1.82 percent, to 11,022.06. The gain helped erase some of the losses from heavy selling earlier in the week, though the blue chips still remain down by more than 360 points, or 3.2 percent. The Standard & Poor’s 500 index advanced 23.31, or 1.97 percent, to 1,209.18 and the Nasdaq composite index rose 30.89, or 1.43 percent, to 2,186.57.

Advancing issues outnumbered decliners by nearly 3 to 1 on the New York Stock Exchange, where consolidated volume came to 5.73 billion shares, compared with 4.66 billion traded Wednesday.

The dollar was mixed against other major currencies Thursday, while gold prices fell.

Light, sweet crude for November delivery rose $2.29 to settle at $108.02 a barrel on the New York Mercantile Exchange.