(Bloomberg) -- Another week, another massive IPO stumbling in its debut.

Last week it was Uber Technologies Inc. showing weakness out of the gate. Now Avantor Inc. isn’t faring much better. The pricing pushback in 2019’s two biggest IPOs represents a break from recent large listings, and a threat to upcoming debuts like WeWork Cos. and Airbnb Inc.

Avantor’s initial public offering priced at the bottom of a reduced range on Thursday, 30% below the original terms set on May 3. Despite the reduced valuation, shares fell as low as the $14 offering price during Friday’s initial trading. Uber’s shares fell 7.6% from a lower-than-expected IPO price in their May 10 debut, the weakest start since the 2008 financial crisis among U.S. companies that had just raised billions of dollars.

Other recent IPOs traded much better at first. Among the last 15 U.S. companies whose IPOs raised at least $1 billion, thirteen rose from their IPO price in their first session. That includes household names like Lyft Inc. and TradeWeb Markets Inc., plus some less familiar stocks such as AXA Equitable Holdings and VICI Properties Inc.

This is all by design. IPOs are typically priced at a 10% to 15% discount to the company’s supposed valuation to pay investors for taking on the extra risk. Without the expectation of a so-called pop, investors could skip the IPO and buy shares on the open market. Avantor shares are currently trading about 1% above their IPO price.

To contact the reporter on this story: Drew Singer in New York at dsinger28@bloomberg.net

To contact the editors responsible for this story: Brad Olesen at bolesen3@bloomberg.net, Steven Fromm

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