Founders wield outsize influence over many of Silicon Valley’s most successful public companies through their shareholdings. But lately a growing number of tech firms are setting limits on founder power, partly in response to investor backlash.

Messaging service Slack, which is expected to go public next year, adopted rules in December that so-called supervoting shares held by co-founder Stewart Butterfield and other insiders would expire seven years after its IPO, according to public filings. Another high-profile firm, Uber, plans to go public with only one class of stock, a spokesman said. Uber eliminated supervoting shares earlier this year, following the ouster of co-founder Travis Kalanick as CEO.