Despite its decent aftermarket performance, the recent IPO by Cardio3 Biosciences S.A. likely won't be the starting gun for a European IPO window. Investors say that a weaker general market, fewer specialist investors and less appetite for risk means Europe is, at least right now, a less fertile environment for IPOs.

On July 5, cardiovascular company Cardio3 raised €23 million ($29.9 million) on NYSE Euronext Brussels and NYSE Euronext Paris through the sale of 1.4 million shares at €16.65, the low end of its €16.65-€19 range. The deal values the company at €102 million ($132.8 million).