As Best Buy Co. (BBY) gets set to report fourth-quarter results Thursday, Wall Street is already pricing in big market-share gains for the retailer tied to the recent demise of Circuit City Stores Inc. (CCTYQ).

Closing at $33.46 on Wednesday, Best Buy shares have risen 31% since Circuit City wrapped up liquidation sales and shut its 567 stores March 8, worrying some Best Buy watchers of pressure Thursday and beyond.

"With high expectations for the quarter going into the earnings release, we would look for a pull back in the share price to the high $20's," Pali Capital analyst Stacey Widlitz said in a note to clients Wednesday.

Even if results meet Wall Street's forecasts, concerns linger over the consumer spending outlook, Best Buy's growth plans and the promotional environment.

Analysts say Best Buy could ultimately gain 30% to 40% of Circuit City's roughly $9 billion in annual sales.

Wedbush Securities analyst Michael Pachter estimates Best Buy, already the largest specialty U.S. electronics retailer, may have picked up five percentage points of market share in the most recent quarter as a result of Circuit City's closing, helping it outperform the overall electronics retailing market.

Analysts polled by Thomson Reuters expect Best Buy to post fourth-quarter earnings of $1.38 a share, compared with $1.71 a year earlier. Same-store sales are expected to fall 6.9%.

But forecasts for the quarter and for the February 2010-ending fiscal year have been increasing in recent weeks. Wall Street's consensus forecast for fiscal 2010 is for earnings of $2.47 a share on a 2.4% decline in same-store sales.

Best Buy on January 9 said it expected fiscal 2009 earnings to range from $2.50 to $2.70 a share, and it promised to provide its first take on fiscal 2010 on Thursday.

Credit Suisse analyst Gary Balter said Operating Chief Brian Dunn, who replaces Chief Executive Brad Anderson in June, may be the one providing direction on the current year.

"There is a stock risk that he discusses moving closer to price parity with Wal-Mart and Amazon, the current competitors now with Circuit City out of the picture," Balter said in a recent note. "He may also take a more conservative view of the outlook, a stance we often see when a new leader takes charge. Both may send the stock lower on earnings day."

While Wal-Mart Stores Inc. (WMT) and Amazon.com (AMZN) are often talked of as the other chief beneficiaries of Circuit City's exit, don't overlook a small army of appliance and furniture dealers that are adding electronics to their stores.

Facing weak sales in those existing product categories, local dealers hope to offer the same kind of personal attention that benefits Best Buy's sales.

At a conference in New Orleans earlier this month, a $12 billion buying group for independent retailers, The Nationwide Marketing Group, touted opportunities for its thousands of members to expand into electronics. Robert Weisner, executive vice president and director of the group, predicted Nationwide members carrying electronics could jump from 500 to more than 1,000 in the next five years, according to a published report.

Independent and regional electronics dealers, as well as office-supply chains like Office Depot Inc. (ODP) and old-line retailers like Sears Holdings Corp.'s (SHLD) Sears and Kmart chains are also hoping to take a chunk of sales and could provide renewed competition in the category.

"We are certainly happy with the opportunity that (Circuit City's closing) provides both of our formats," said Karen Austin, president of electronics for Sears Holdings, in a recent interview. "We have all the top brands, we have knowledgeable sales staff, and there's less and less of that."

-By Mary Ellen Lloyd, Dow Jones Newswires, 704-948-9145; maryellen.lloyd@dowjones.com