Premarket Roundup: Corp. Executive Board, Covance

Among the premarket stories for Tuesday, Sept. 22, from AP Financial News:

NEW YORK (AP) — William Blair & Co. upgraded consultancy Corporate Executive Board Co. to its highest rating Tuesday, saying corporate spending on consulting services will improve next year.

NEW YORK (AP) — A Jefferies analyst upgraded shares of drug development services company Covance Inc. Tuesday, a day after the stock took a downturn.

NEW YORK (AP) — Shares of oil and gas exploration company Unit Corp. have risen to a fair value, said an analyst on Tuesday as he downgraded the stock.

NEW YORK (AP) — Shares of Louisiana-Pacific Corp. fell Tuesday after the wood products company said it will sell 18 million shares of its common stock through a public offering, a move that may dilute the stakes of existing stockholders.

HARTFORD, Conn. (AP) — Whiting Petroleum Corp. is producing more oil than expected from its North Dakota site and may even increase its 2009 guidance when it posts third-quarter results, an analyst said Monday as he raised his earnings estimate and price target.