From Deputy Business Editor Rami Grunbaum:

Northstar Neuroscience, which went public with a bang in early May, slid sharply today to close below its offering price for the first time.

With demand evidently strong, the Seattle medical device company priced its offering May 5 at $15, a dollar above its $12 to $14 expected range, and sold 1.1 million more shares than originally planned. The stock traded up nearly 10 percent its first day, and has been as high as $17.75.

But Wednesday, it dropped 13 percent, or $2.02, closing at $13.48.

Qualifying as a so-called 'broken IPO' is never good. On the other hand, Northstar held up better than Internet phone company Vonage, which began trading today and promptly fell more than 12 percent below its offering price.