On Thursday afternoon, shares of SpaceX and Tesla fell by approximately 9% and 11%, respectively. In the wake of the U.S. midterm elections, investors are concerned that Musk may face a fresh round of congressional scrutiny, and that both companies could be subjected to tighter regulatory oversight. This decline coincided with a broad sell-off across the tech sector; since Tuesday's close, the two companies have shed a combined market value exceeding $420 billion.