Last week was meant to mark a return to health for the tech IPO market, but instead it came down with a nasty summer cold.

When the week began, 11 tech companies had gone public so far in 2017, beginning withSnap's offering in early March. Many of those IPOs, like Snap and Cloudera, priced above their original pricing ranges, suggesting a strong demand among institutional investors. And all but two of them – AI startup Veritone and Chinese data-center company GDS Holdings – were trading above their offering prices.

With major stock indexes trading near record highs, the week should have been a good one. Especially with Blue Apron, the best-known tech IPO since Snap, emerging from the pipeline. Instead, Blue Apron priced its IPO at $10 a share, below the initial range of $15 to $17 a share. Blue Apron couldn't muster the first-day pop that most tech IPOs enjoy, closing at $10 a share Thursday. The company fell 7 percent the next day, closing at $9.34 a share...