Liam O’Connor, vice president of global supply management, has resigned from the electric-car maker, said the people, who requested anonymity because the information hadn’t been made public. Tesla representatives didn’t immediately respond to a request for comment. The stock fell after the close of regular trading.

O’Connor, who joined Tesla (TSLA) in March 2015 from Apple, is at least the fifth senior executive to be parting ways with the carmaker within the span of a few weeks. The company has lost its chief accounting officer and heads of human resources and communications this month. Justin McAnear, the vice president of worldwide finance, is slated to leave in early October.

The flight of top managers has rattled investors because it’s coincided with a series of missteps by Musk, 47. Tesla is facing probes by the U.S. Department of Justice and Securities and Exchange Commission and investor lawsuits related to his short-lived attempt to take the company private. The billionaire has himself been sued for calling a cave rescuer a pedophile and smoked marijuana during a livestreamed podcast with a comedian.

Musk, who’s both chairman and chief executive officer, announced a series of promotions earlier this month aimed at rebuilding his senior management team from within. His most significant move was to elevate Jerome Guillen to automotive president, a newly created role that includes coordinating Tesla’s vehicle supply chain. That job description suggests Guillen’s job probably would have involved overseeing O’Connor.

Tesla shares fell 0.3% to $297.35 as of 6:27 p.m. Thursday in New York. The stock was down 4.2% this year through the close.