NEW YORK (Reuters) - U.S. stocks closed steeply lower after a late-session sell-off on Wednesday as investors weighed surging COVID-19 infections and mounting shutdowns against encouraging vaccine developments. While the three major U.S. stock indexes oscillated through much of the day, with economically-sensitive cyclicals and small caps leading the way, they closed sharply in the red. “It’s a confused market because portfolio managers don’t know which time period to focus on,” said Tim Ghriskey, chief investment strategist at Inverness Counsel in New York. “It’s this trade-off between the near term over the six to nine months of continued spread of the virus and the period after that when everyone’s vaccinated and the virus is eradicated.” “There’s a lot of issues out there but the decided bias has been toward value and cyclicals,” Ghriskey added. Pfizer Inc PFE.N and its German partner BioNTech BNTX.O revealed a 95% success rate at the conclusion of their COVID-19 vaccine trial, just days after Moderna Inc MRNA.O announced a similar rate of success in preliminary data from its vaccine candidate. Market participants have been greeting vaccine developments with guarded optimism, but that is being tested as global new infections soar to record levels, and roll-backs of reopenings and new lockdowns continue to mount. The Dow Jones Industrial Average .DJI fell 344.93 points, or 1.16%, to 29,438.42, the S&P 500 .SPX lost 41.74 points, or 1.16%, to 3,567.79 and the Nasdaq Composite .IXIC dropped 97.74 points, or 0.82%, to 11,801.60. All 11 major sectors in the S&P 500 closed in negative territory, with energy shares .SPNY suffering the biggest loss. Third-quarter reporting season has reached the final inning, with 468 of the companies in the S&P 500 having reported. Of those, 84.4% have surprised consensus to the upside, according to Refinitiv. Boeing Co BA.N initially provided the biggest lift to the Dow after the Federal Aviation Commission green-lighted the planemaker"s grounded 737 MAX aircraft to resume flights, but its shares later reversed course, shedding 3.2%. Target Corp TGT.N handily beat quarterly profit and sales estimates, boosted by a 155% jump in comparable digital sales. The retailer"s stock rose 2.3%. Lowe"s Companies Inc LOW.N dropped 8.2% after the home improvement retailer forecast lower-than-expected holiday quarter earnings as it beefs up its online business and doles out employee bonuses to ease pandemic-related hardship. Declining issues outnumbered advancing ones on the NYSE by a 1.52-to-1 ratio; on Nasdaq, a 1.57-to-1 ratio favored decliners. The S&P 500 posted 30 new 52-week highs and no new lows; the Nasdaq Composite recorded 142 new highs and nine new lows. Volume on U.S. exchanges was 11.42 billion shares, compared with the 10.44 billion average over the last 20 trading days.