T. Rowe Price, Guess: Ratings Changes

BOSTON (TheStreet) -- TheStreet.com's stock-rating model upgraded life sciences company Bruker(BRKR Quote) to "buy."

The numbers: Second-quarter net income decreased 41% to $13 million, or 8 cents a share, as revenue dropped 19% to $253 million. Bruker's gross margin rose from 44% to 47%, but its operating margin declined from 9% to 8%. A quick ratio of 0.6 indicates poor liquidity. Its debt-to-equity ratio of 0.5 reflects conservative leverage.

The stock: Bruker shares have more than doubled this year, beating major U.S. indices. The stock trades at a price-to-earnings ratio of 27, a premium to the market, but a discount to life science peers. The company doesn't pay dividends.

The model upgraded clothing retailer Guess(GES Quote) to "buy."

The numbers: Fiscal second-quarter net income rose 11% to $60 million, or 64 cents a share, as revenue grew 2% to $500 million. The company's gross margin was unchanged at 45%, and its operating margin increased from 12% to 14%. A quick ratio of 1.9 reflects ample liquidity. Guess holds minimal debt.

The stock: Guess shares have more than doubled this year, outpacing major U.S. indices. The stock trades at a price-to-earnings ratio of 17, a discount to the market and apparel retailers.

The model upgraded National-Oilwell Varco(NOV Quote), a maker of oil and gas drilling equipment, to "buy."

The numbers: Third-quarter profit dropped 30% to $385 million, or 92 cents a share, as revenue decreased 15% to $3.1 billion. The company's gross margin fell from 35% to 29%, and its operating margin declined from 23% to 20%. The company has an admirable financial position, with $3.2 billion of cash and just $884 million of debt.