Shares of

Shanda Interactive

( SNDA) tumbled 19% in after-hours trading Monday after the Chinese operator of online games posted fourth-quarter results that were far short of expectations. Shanda recorded a loss of $66.8 million, or 94 cents per American Depositary Share. The loss included an impairment charge totaling $64.6 million, or 90 cents per ADS, related to Shanda's 38% stake in South Korean online game company Actoz. Analysts polled by Thomson First Call expected earnings of 26 cents a share, before the charge. Shanda reported revenue of $44.7 million, down 16% from a year earlier and well below Wall Street's projection of $59 million. The company's shares sank $3.27 to $13.66 in late trading.

PDL BioPharma

(PDLI) - Get Report

advanced after the biopharmaceutical company posted better-than-expected fourth-quarter earnings and offered a sales forecast that topped projections. The company posted a net loss of $23.1 million, or 22 cents a share, narrowed from $14.6 million, or 15 cents a share a year earlier. Excluding certain items, earnings were $7.5 million, or 6 cents a share, while the comparable year-earlier loss totaled $11.9 million, or 12 cents a share. Total revenue surged to $83.7 million from $22.8 million. Analysts were expecting the company to post earnings of 5 cents a share, before items, and revenue of $88.5 million.

For 2006, the company projects total operating revenue of $405 million to $435 million, above Wall Street's forecast of $386.2 million. The company reported 2005 revenue of $276.9 million. Shares of PDL BioPharma gained 65 cents, or 2.1%, to $31.20 in after-hours trading.

Standard & Poor's reportedly will add

Chesapeake Energy

(CHK) - Get Report

to the

S&P 500

index. The natural gas concern will replace struggling auto-parts maker

Dana

( DCN). Chesapeake shares rose $1.13, or 3.9%, to $30.05 in late trading.

Conseco

(CNO) - Get Report

shares rose in late trading even after the insurance company reported a fourth-quarter earnings decline that fell short of Wall Street forecasts. The company reported earnings of $67.6 million, or 42 cents a share, compared with $76.9 million, or 46 cents a share, a year earlier. Operating income rose 5% to $70.4 million, or 44 cents a share. Analysts expected operating earnings of 45 cents a share. Revenue fell to $1.08 billion from $1.11 billion a year ago.

Looking ahead, the company said it expects 2006 operating earnings will at least be at the low end of the First Call analyst range, which is $1.85 a share. The average expectation is $1.90 a share. Conseco shares rose 99 cents, or 4%, to $25.33 after hours.

Cerus

(CERS) - Get Report

shares slipped slightly after the drugmaker said it plans to offer 4.5 million common shares to the public. The offering will be made pursuant to an effective shelf registration statement that was filed with the

Securities and Exchange Commission

. The company will grant the underwriters an option to purchase up to an additional 675,000 shares to cover overallotments. Shares of Cerus slipped 12 cents, or 1%, to $11.50 in after-hours trading.