NEW YORK — Wall Street has had a mixed day, with stocks moving in and out of positive territory while investors digested a range of economic developments.

Investors initially sent shares sharply higher as regulators allowed the mortgage companies Fannie Mae and Freddie Mac to buy more loans. Federal Reserve Chairman Ben Bernanke also lifted stocks when he told Congress the central bank will remain vigilant about the weakened economy.

Both developments have boosted confidence amid increasing signs of a slowing economy and rising inflation. The rising price of oil, which made it past $102 a barrel, did inject some uneasiness into the market.

According to preliminary calculations, the Dow Jones industrial average — now up four straight sessions — rose 9.36, or 0.07 percent, to 12,694.28.

Broader indexes were narrowly mixed. The Standard & Poor's 500 index fell 1.27, or 0.09 percent, to 1,380.02, and the Nasdaq composite index rose 8.79, or 0.37 percent, to 2,353.78.