Novastar Financial ( NFI) plummeted some 28% in after-hours action Tuesday as the nonprime lender posted dismal fourth-quarter results. The Missouri-based company lost $11.9 million from continuing operations, or 32 cents a share, compared with last year's profit of $28.5 million, or 73 cents a share. Analysts polled by Thomson Financial were looking for flat year-over-year income.

The Missouri-based company also announced it may shed its status as a real estate investment trust post-2007, given that it is compelled as a REIT to pay out 90% of taxable income via dividends, and expects to see "little, if any, taxable income" from 2007 through 2011. Shares were losing $4.88 to $12.68.

Semiconductor Pixelworks ( PXLW) announced Samsung Electronics will use its "Bluejay" chip, which eliminates video distortion, in two of its slim, traditional-model television designs. Shares of the Tualatin, Ore.-based company were gaining 22 cents, or 10.8%, to $2.25.

AmSurg ( AMSG) climbed after the Nashville-based operator of ambulatory surgery centers reported fourth-quarter income from continuing operations of $10 million, or 33 cents a share, up from $8.4 million, or 28 cents a share, a year ago. Revenue rose 17% to $118.9 million. The Street was looking for 32 cents a share on $116.5 million revenue. The company also expects 2007 sales of $510 million to $530 million -- at least $46.4 million above estimates. Shares were up $1.71, or 7.5%, to $24.65.

Nanogen ( NGEN), based in San Diego, narrowed its fourth-quarter loss to $11.2 million, or 17 cents a share, from $69.7 million, or $1.27 million a year ago. The diagnostic-products maker's sales soared to $8.7 million from $3.1 million last year. Shares were adding 7 cents, or 4.8%, to $1.52.

Dyax ( DYAX) was plunging after the Cambridge, Mass., biotech and Genzyme ( GENZ) ended their nine-year joint venture to develop a treatment called DX-88 for hereditary angioedema, a rare blood disease. Dyax will retain all rights to the drug and $17 million besides, while Genzyme will receive 4.4 million Dyax shares. Dyax will continue to develop the drug and says this decision won't skew anything in the way of that. Dyax shares were declining 68 cents, or 15.7%, to $3.65. Genzyme's shares were unchanged after closing the regular session at $65.75, up 55 cents.

Hawaiian Airlines' parent company, Hawaiian Holdings ( HA), was lower on fourth-quarter operating losses that widened to $13.9 million from $10.3 million last year. Overall losses narrowed to $9.6 million, or 20 cents a share, from last year's $19.5 million, or 43 cents a share; also, sales edged up 3.6% to $219.6 million. But revenue per passenger was down 1.8% to 10.83 cents, and load factor (a measure of passenger traffic) was down 4.5 points to 85.2%. Shares were losing 28 cents, or 4.4%, to $6.05.

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