VentureBeat

There was struggling Classmates.com.

Now it’s more data storage companies. They’re all losing money, but running like lemmings to go public before the IPO window shuts. The window of IPO opportunity is still open, but precariously so, because the liquidity crisis hitting the markets is making investors very nervous.

The latest is 3Par, of Fremont, which has filed to raise $100 million even though its losses are widening ($4.7 million in the quarter ending June 30, up from $2.2 million the same quarter last year). Its sales are growing, but the cost of getting those sales is growing just as quickly, as its filing shows.

OnStor, a Campbell, Calif. company offering data storage for large companies, is preparing to go public, after a rocky ride. Isilion Systems went public a while ago, and is losing more money than expected. Data Domain went public, and saw its shares rise despite seeing deepening losses. Other companies, such as Siliconstor, are selling off to others.

Notably, some of these companies may feel pressure from their investors to go public. Mayfield Fund holds 19.5 percent of the 3Par, Menlo Ventures owns 17.8 percent, and Worldview Technology Partners has 15 percent, most of these having held their stakes for more than eight years. WorldView, in particular, is under pressure, having had a long struggle with its portfolio (as we’ve reported) - and is exposed to storage more than most. It’s also an investor in OnStor, for example.

3Par has absorbed more than $180 million over the years. 3Par at least provides “virtualization” technology for data storage, which gives it some buzz at a time when virtualization is hot (VMware, a leader in the virtualization sector — though not storage focused — just had the largest tech IPO since Google).

3Par’s filing wasn’t unexpected. We mentioned its plans here.