NEW YORK ( TheStreet) -- Independent petroleum company Tesoro ( TSO) has been raised to overweight from equal weight at Barclays Capital.

Shares were popping by 2.5% to $23.72 in premarket trading Wednesday.

A group of unidentified bond investors calling themselves Walnut Place are challenging the $8.5 billion settlement that Bank of America ( BAC) reached with investors of mortgage-backed securities last week, the Wall Street Journal reported. Bank of America shares were falling 1.6% to $10.82.

Verizon Wireless ( VZ), the nation's largest wireless carrier, is getting rid of its unlimited data plan for new smartphone customers starting Thursday, shifting instead to limited data plans that give users between 2 and 10 gigabytes of data each month.

Shares of Verizon were falling 1.5% to $37.25.

Berkshire Hathaway ( BRK.A) is part of a bidding group in talks to buy Citigroup's ( C) consumer-lending business, The Wall Street Journal reported, citing people familiar with the matter.

Citigroup shares were down 0.6% to $42.30 in premarket trading Wednesday.

Engineering company Siemens ( SI) is getting ready to commission its first solar-thermal power plant within two months and is looking for financing that will triple its capacity, Bloomberg reported, citing the company's head of solar energy in Spain.

Shares were lower by 0.5% at $135.88.

Sterne Agee analysts increased their third-quarter profit estimates for iPhone maker Apple ( AAPL) to $5.95 from $5.75 a share.

Shares were down 0.3% at $348.24.

Drugstore chain Walgreen ( WAG) reports that its June comparable-store sales rose 4.8%, beating Wall Street estimates.

Walgreen shares were spiking by 0.2% at $42.80.

Low-fare airline Spirit Airlines ( SAVE) has been initiated at buy at Dahlman Rose .This week, the stock was initiated at overweight at Barclays Capital, overweight at Morgan Stanley and buy at Citigroup, Shares were unchanged at $12.15.

BMO analysts have initiated coverage of enterprise software provider Informatica ( INFA) at outperform.

-- Written by Andrea Tse in New York.

>To contact the writer of this article, click here: Andrea Tse.


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