Tech stocks were lower Tuesday, as an earnings miss for Ericsson ( ERIC) helped temper expectations for the sector. The Swedish telecom's shares plummeted 24.6% after missing Wall Street's third-quarter profit outlook. Net income fell 36% from a year ago to $622 million, while revenue gained 6% to $6.78 billion. Analysts were expecting sales of $6.92 billion, according to Thomson Financial. Ericsson shares were falling $10.08 to $30.85. Yahoo! ( YHOO) also was shedding 3.5% as the Internet giant prepares to report earnings after the bell. Shares were falling 97 cents to $26.89. EchoStar Communications ( DISH), however, was rising 3.9% after merger speculation around the Dish satellite television provider picked up. AT&T ( T), rumored to be interested in EchoStar's TV operations if it splits broadcasting operations and wholesale satellite transmission business, reportedly hired Goldman Sachs to advise it on a potential deal. A Citi Investment Research note also said a buyout is likely, according to the Associated Press. Shares were gaining $1.89 to $50.93. Ericsson, Yahoo! and EchoStar are components of the Nasdaq 100, which was off 7.30 points to 2151.62. Among other movers, ValueClick ( VCLK) shares were sinking 9.9%, after the Internet advertising player lowered third-quarter and full-year revenue projections. The company now expects third-quarter sales of between $156 million and $157 million, down from its prior range of $155 million to $165 million. Thomson Financial's analyst poll pegs third-quarter revenue at $159 million. For the full year, ValueClick now expects sales of between $635 million and $640 million, below its earlier outlook of $645 million to $660 million and the Street's expectation of $650 million. Shares were losing $2.75 to $25.03. DealerTrack Holdings ( TRAK) was shedding 7.4% after the software maker for the auto retail industry lowered its full-year guidance and announced an offering of 4 million shares of common stock. DealerTrack will offer half the shares, while selling shareholder Credit Management Solutions is offering the other half. Underwriters have the option of buying an additional 600,000 shares. Proceeds from the sale will be used for general corporate purposes. The company also lowered its expectations for non-GAAP earnings of between $1.04 and $1.05 a share, vs. the previous range of $1.06 to $1.07 a share. Analysts polled by Thomson Financial expect earnings of $1.07 a share. DealerTrack shares were falling $3.63 to $45.43. Overstock.com ( OSTK) was losing 10%, after Stifel Nicolaus downgraded the online retailer to sell from hold. Shares fell $3.39 to $30.63. On the positive side, networking and communications equipment provider Adtran ( ADTN) was adding 6.9% after beating Wall Street's third-quarter earnings expectations, despite missing revenue projections. The company reported sales of $123.8 million and diluted earnings of 31 cents a share for the quarter, vs. revenue of $123.7 million and earnings of 28 cents a share in the year-ago period. Analysts expected earnings of 29 cents a share on revenue of $124.6 million. Shares were gaining $1.54 to $23.90.