It's never a good sign when a technology company pulls its IPO, but when this starts happening once a day, it gets a bit alarming.

Friday afternoon, Silicon Valley's ANDA Networks, a maker of Ethernet technology for access networks, said it would withdraw its filing, citing unfavorable market conditions. The company, which had hired Thomas Weisel and RBC Capital Markets to lead the underwriting,  was one of the last companies to file for an IPO in 2007, submitting its documents Dec. 21.

On Thursday, Aprimo Inc., which develops marketing software, yanked its offering (Weisel was also underwriting this one, along with Morgan Stanley).

Of course, two withdrawals do not make a trend (three might -- stay tuned). But with the way the market is going, underwriters and investors in the handful of other technology companies that have filed to go public this year have to be sweating.

Recent filers of S-1's (and, potentially, Form RWs), include: SolarWinds Inc., a network management software company backed by Bain Capital and Insight Ventures; and online marketing startup Eyeblaster Inc., also backed by Insight as well as a handful of high-net-worth individuals. -- Olaf de Senerpont Domis 

See ANDA profile from Renaissance Capital's IPOhome
See Aprimo profile from Renaissance Capital's IPOhome
See March 24 story from TheDeal.com