The stake is worth about $50 million, according to a person familiar with the matter, who asked to not be identified discussing confidential information. A representative for Lyft didn’t immediately provide a comment. A representative for Engine Capital declined to comment. Shares in Lyft have lost more than a third of their value over the last 12 months, giving it a market capitalization of about $5.3 billion. The stock rose 4.1% at 1:03 p.m. in New York trading Tuesday. Investors are worried about the future of Lyft’s model, which is reliant on human drivers, as autonomous vehicles are becoming more commonplace in the US. Since Lyft does not have an international business outside of the US and Canada, it’s more exposed to domestic competitors such as larger global rival Uber Technologies Inc. and emerging autonomous vehicles. Uber already has an exclusive partnership with Alphabet Inc.’s Waymo to provide driverless rides in Austin and is planning a similar offering in Atlanta. Meanwhile, Elon Musk intends for Tesla Inc. to launch robotaxis in Austin and California this year. Lyft has struck a few of its own autonomous partnerships, the first of which is set to launch later this year in Atlanta.