NEW YORK, Oct 12 (Reuters) - U.S. stocks finished lower on Tuesday, extending losses late as investors grew more jittery in the run up to third-quarter earnings, while a jump in Tesla shares helped support the market. Adding to investor caution, the Federal Reserve is expected to release minutes on Wednesday from its last policy meeting, which market participants will scour for hints about when the U.S. central bank could begin tapering its massive bond-buying program. All three major U.S. stock indexes ended in the red with the Dow down the most, weighed by healthcare (.SPXHC) and industrials (.SPLRCI). Earnings unofficially kick off this week with results from JPMorgan Chase & Co (JPM.N) on Wednesday and other banks to follow. JPMorgan"s shares shed 0.8% on the day, while the S&P 500 banks index (.SPXBK) edged down 0.6%. Analysts expect to see strong U.S. profit growth for the third quarter. But a number of companies have warned of issues and investors are worried about how supply chain problems and higher prices will affect businesses emerging from the coronavirus pandemic. "For the most part, institutional portfolio managers are of the view - let"s see what earnings look like and how much of a negative impact is being seen from shortages, higher rates and supply chain bottlenecks," said Michael James, managing director of equity trading at Wedbush Securities in Los Angeles. "A lot of those factors are currently reflected where equity prices are now." The Dow Jones Industrial Average (.DJI) fell 117.72 points, or 0.34%, to 34,378.34, the S&P 500 (.SPX) lost 10.54 points, or 0.24%, to 4,350.65 and the Nasdaq Composite (.IXIC) dropped 20.28 points, or 0.14%, to 14,465.93.Six of the 11 major sectors of the S&P 500 ended the session in the red, with communications services (.SPLRCL) suffering the steepest percentage loss.Tesla (TSLA.O)advanced 1.7% after data showed the electric vehicle maker sold 56,006 China-made vehicles in September, the highest since it started production in Shanghai about two years ago. The company"s shares provided the biggest boost to the S&P 500 and the Nasdaq. read more Shares of American Airlines Group (AAL.O) rose 0.8% after the company estimated a smaller-than-expected adjusted loss for the third quarter and signaled improved bookings for the rest of the year. read more MGM Resorts (MGM.N) surged 9.6% after of Credit Suisse upgraded the stock to "outperform" from "neutral." Nike Inc (NKE.N) gained 2.0% after Goldman Sachs initiated coverage with a "buy" recommendation. Investors also weighed comments from Fed Vice Chair Richard Clarida, who said the central bank has all but met its employment goal for reducing its bond buying program. read more U.S. data showed the labor market remained tight, with a record number of Americans quitting their jobs and job vacancies numbering more than 10 million, stoking inflation fears as employers hike wages to attract and retain workers. read more Wednesday"s consumer price index report will attract attention from investors seeking clues about inflation. Advancing issues outnumbered declining ones on the NYSE by a 1.38-to-1 ratio; on Nasdaq, a 1.42-to-1 ratio favored advancers. The S&P 500 posted 10 new 52-week highs and 10 new lows; the Nasdaq Composite recorded 46 new highs and 94 new lows. Volume on U.S. exchanges was 9.17 billion shares, compared with the 10.80 billion average over the last 20 trading days.