Shares of health care software maker

Impac Medical Systems

(IMPC)

closed up 18% on their trading debut Wednesday.

While Impac recorded one of the better first-day performances of the year, according to data from IPO.com, it fell well behind average debut gains of 67% back in the IPO heydays of 1999.

The company's IPO comes at a horrible time for the new-issues market. So far this year, only 77 IPOs have been brought to the market, compared with 526 back in 1999. Several companies have decided to postpone their public offerings so far this year, the latest being

Safety Insurance Group

and

Bancshares of Florida

just last week.

"The conventional thinking is they can come public at a higher valuation if they wait," said David Menlow, president of IPOFinancial.com.

Impac, which provides information-technology software systems for cancer centers, sold 2.19 million shares at $15 a share, the low end of $15 to $17 price range, in a deal valued at $35 million. Co-managers on the deal were SG Cowen and U.S. Piper Bancorp Jaffray.

The stock finished the day up $2.72, at $17.72, on volume of 960,100 shares.

Menlow said the IPO performance was far in excess of what he had expected, and that possibly the credit should go to lead underwriter Thomas Weisel Partners for its work in bringing the issue to market. "Thomas Weisel has not been a lead manager in two years," he said. "They are re-establishing their reputation in bringing a company public."

The company reported a bottom-line loss of $3.37 million, or 56 cents a share, in its fiscal 2002 year, partly a result of an $8.55 million charge for the accretion of redeemable convertible preferred stock.

Meanwhile, sales at Impac rose to $45.7 million in 2002 from $33.9 million in the year-ago period. And the software maker has been profitable in the past, posting earnings 25 cents a diluted share in 2001.

The company's main competitor is

Varian Medical Systems

(VAR) - Get Report

, a manufacturer of both medical hardware and software products, which tried to acquire it two years ago. The government blocked the merger for antitrust reasons.