With the pricing of IPOs by Caliper Technologies Corp. and Maxygen Inc. last week, the financing window for biotech companies has blown open with astonishing speed, deal size and valuations.

Four biotech IPOs now have closed in the past month - three in the past week - and each has raised more than $70 million. MAXY (Redwood City, Calif.) raised $96 million, while CALP (Mountain View, Calif.) raised $72 million. The previous Friday, Tularik Inc. (TLRK, South San Francisco, Calif.) raised $97.3 million. And on Nov. 17, combinatorial chemistry play Symyx Technologies Inc. (SMMX, Sunnyvale, Calif.) raised $77.5 million.

Investors are obviously hungry for shares, as all four companies raised more money than planned. Indeed, MAXY raked in $21.2 million more than it had targeted for its DNA shuffling business. TLRK, which is developing drugs for cancer, infectious diseases, metabolic diseases, inflammation and immune disorders, grabbed an additional $16.1 million; CALP, the lab-on-a-chip company, was $12 million on the upside; and SMMX beat its range by $8.5 million.

In the aftermarket, the smallest first day move was TLRK, whose $6.125 rise to $20.125 (40 percent) paled in comparison to MAXY's gain of $26.063 to $42.063 on 7.7 million shares (163 percent) and CALP's $23.25 uptick to $39.25 (145 percent). SMMX was up $8.438 (60 percent) on its first day to $22.438.

The gains left MAXY with a first-day valuation of $1.26 billion. Similarly, CALP was awarded with a $797 million valuation on Day One, while SMMX finished with a valuation of $623.8 million.

Meanwhile, investors revisited TLRK on Friday, as the stock soared $15.75 (79 percent) to $35.625 on 693,100 shares on no news. The company is now valued at $1.5 billion, compared to its first day market cap of $845.3 million.

Dynamics point up

New money from aggressive growth and momentum investors has pushed open the window, along with technology investors who are looking for places to park some dot.com profits. "The breadth of the buyers is big," said Stuart Duty of U.S. Bancorp Piper Jaffray. "We're seeing tech money looking for fresh ideas - momentum investors who are investing across growth technologies - in addition to the traditional biotech investors."