Key TakeawaysNvidia shares lost ground Wednesday, extended Tuesday's losses following reports the U.S. Department of Justice (DOJ) sent subpoenas to the chipmaker as part of an antitrust investigation.The decline in Nvidia's stock price also comes after the chipmaker's sales forecast may have fallen short of investors' lofty expectations, despite beating analysts' estimates.The recent downturn in Nvidia stock could intensify investor scrutiny of other AI stocks, with investors likely to be watching Broadcom ...