U.S. stock indexes squandered a powerful, technology-led rally Monday, with gains collapsing as California signaled that it was re-imposing some restrictions on business reopenings as coronavirus cases rise in the Golden state. The Nasdaq Composite index /zigman2/quotes/210598365/realtime COMP +0.55% swung from nearly a 2% gain early Monday to a decline of about 2.1% at about 10,390. The day's reversal represents that sharpest intraday turnaround since the Nasdaq was up 2.95% on April 7 to end down 0.3%, according to Dow Jones Market Data. Tech-related names like Tesla /zigman2/quotes/203558040/composite TSLA -0.64% , whose shares were enjoying a 14% gain earlier in the session, closed off 3.1% on the session, after touching a record-setting market value of more than $320 billion. California also took a U-turn on Monday, with Gov. Gavin Newsom ordering every county bar in the state to shutter , as well as restaurants offering indoor dining, movie theaters and wineries. Meanwhile, the Dow Jones Industrial Average /zigman2/quotes/210598065/realtime DJIA -0.04% closed with a meager gain of 0.1% at around 26,086, but had hit a intraday peak at 26,639, while the S&P 500 index finished down 1% after hitting an intraday peak at 3,235. Monday's opening gains had been powered by news on the health front. the Food and Drug Administration granting Pfizer Inc. /zigman2/quotes/202877789/composite PFE -0.05% and BioNTech SE /zigman2/quotes/214419716/composite BNTX +2.13% , on two of their COVID-19 vaccine candidates, accelerated status.