Uber Technologies grew to be the nation’s most valuable startup thanks to support from some of the biggest investors around. That support became a liability when the ride-hailing giant made its stock-market debut this month.

Some pre-IPO Uber shareholders including BlackRock, the world’s largest money manager, and prominent tech investor Tiger Global Management took a pass on buying more shares in the listing, content that they already owned plenty, people familiar with the matter said. Instead, they tried to sell stock before or as part of the initial public offering.