NEW YORK (CNN/Money) - Stocks tipped higher at the open Tuesday, bouncing back after the previous session's consolidation.

But gains were muted by a warning from Nokia, news of a possible investigation into Freddie Mac, and some weakness in chip makers.

At 9:35 a.m. ET, theDow Jones industrial average (up 69.70 to 9049.70, Charts) was back above 9,000 and the Nasdaq composite (up 14.48 to 1618.45, Charts) and the S&P 500 index (up 6.50 to 982.43, Charts) saw modest gains.

Boeing (BA: up $1.09 to $34.26, Research, Estimates) helped the Dow move higher after Banc of America Securities upgraded the aircraft maker to "buy" from "neutral," and raised its price target on the stock, citing better business trends. Shares of Boeing rose nearly 3 percent in early trading.

Also, pharmaceutical company Geron (GERN: up $1.98 to $8.94, Research, Estimates) jumped up more than 30 percent after the company said it was granted a U.S. patent number for the engineering of some stem cells, which it said could eventually lead to treatments for heart disease, cancer, spinal cord injury, Parkinson's disease and diabetes. The news boosted the drug sector in general.

Meanwhile, investors waited for the release of the Federal Reserve Board's Beige Book at 2 pm. ET, hoping for signs of where the economy, and interest rates, are heading. The Beige Book is essentially a snapshot of where the economy stands in the agency's 12 districts around the nation – and sometimes provides an indication of the Fed's next move.

But, other corporate news muted the gains.

Nokia (NOK: down $0.21 to $17.75, Research, Estimates) slipped more than 3 percent in the early going after the world's largest handset maker warned its second-quarter sales are likely to be at the low end of expectations, citing losses from the weak dollar and the SARS outbreak.

The forecast came on the back of a warning Monday from Nokia's chief rival Motorola (MOT: up $0.10 to $8.78, Research, Estimates) that its sales and earnings for the quarter would fall below previous forecasts. Motorola share rose in early trading.

The semiconductor industry took a hit at the open after Banc of America downgraded several chip makers. Applied Materials (AMAT: down $0.13 to $15.69, Research, Estimates) and KLA-Tencor (KLAC: down $0.56 to $47.44, Research, Estimates) slipped on the rating change.

Meanwhile, shares of mortgage lender Freddie Mac (FRE: up $1.54 to $51.80, Research, Estimates) regained some of their losses from the pervious day despite indications that securities regulators may open a probe into whether the company deferred income to stabilize its results. Shares of the company dropped 16 percent Monday after it announced the resignations of its president and chief operating officer, and the resignation of its chief financial officer.

European markets were mixed in midday trading. Asian-Pacific stocks ended lower overnight.

Treasury prices rose, with the 10-year note gaining 9/32 of a point in price to yield 3.24 percent. The dollar was stronger against the yen and euro.

Brent oil futures slipped 21 cents to $27.30 a barrel in London. Gold sank $5.50 to $357.10 an ounce in New York.