Investing.com -- U.S. stocks pared earlier gains on Wednesday to close slightly lower for the session, as the Leave campaign surged ahead in two closely-watched Brexit public opinion polls, providing downward pressure on oil and global equities.
The Dow Jones Industrial Average fell 48.90 or 0.27% to 17,780.83, while the S&P 500 Composite index lost 3.45 or 0.17% to 2,085.45, as investors remained cautious ahead of Thursday's historic referendum in the U.K. The NASDAQ Composite index, meanwhile, dropped 10.44 or 0.22% to 4,833.32, despite a surge in biotech stocks. On the S&P 500, seven of 10 sectors closed in the red, as stocks in the Energy and Utilities industries lagged. Stocks in the Health Care and Telecommunications sectors led, each gaining more than 0.15% on the session.
Stocks on Wall Street closed lower even as the FTSE 100 gained 57 points or 0.9% to 6,284, closing at a two-week high. After the close of trading in the euro area on Wednesday, a poll from Opinium showed that the Exit vote had taken a slight 45-44% lead, while a TNS survey found that the Leave camp jumped in front by a 43-41% margin, with 16% undecided. Still, British sportsbook Ladbrokes (LON:LAD) placed the probability of Remaining at 73% based on its live odds, down slightly from a 76% chance earlier this week. Notably, it will take the U.K. a minimum of two years to leave the European Union even if the Exit campaign prevails.
As investors remained jittery ahead of the vote, the CBOE's VIX Volatility Index surged above 21.00 at one point in Wednesday's session, before closing at 20.96, near three-month highs. The VIX gained more than three points on the day.
The top performer on the Dow was Merck & Company Inc (NYSE:MRK), which gained 0.88 or 1.56% to 57.13. It came as the NASDAQ IBB Biotechnology ETF soared as much as 2.7%, after receiving a boost from a Medicare report on Wednesday. Stocks such as Merck moved higher after the report showed that annual Medicare spending didn't trigger the initiation of the Independent Payment Advisory Board (IPAB), a mechanism established in order to control costs. Had Medicare spending exceeded a target growth rate, IPAB would have received the authority to enforce cost cuts in Medicare, potentially leading to sharp reductions in drug spending. The worst performer was McDonald’s Corporation (NYSE:MCD), which fell 2.03 or 1.66% to 120.60.
The biggest gainer on the NASDAQ was Celgene Corporation (NASDAQ:CELG), which also rose exponentially following the Medicare report. After gaining 2.48 or 2.56% to 99.34, shares in Celgene (NASDAQ:CELG) are now virtually flat over the last three months. Regeneron Pharmaceuticals Inc (NASDAQ:REGN), Biomarin Pharmaceutical Inc (NASDAQ:BMRN) and Express Scripts Holding Co (NASDAQ:ESRX) were also among the session's top performers, as investors took a collective sigh of relief once the IPAB trigger was averted.
The worst performer was Tesla Motors Inc (NASDAQ:TSLA), which plummeted 22.97 or 10.46% to 196.64 after reports surfaced that the electric car giant has made a $2.8 billion offer to purchase rooftop solar panel corporation SolarCity Corporation (NASDAQ:SCTY). The acquisition represents a bold attempt by Elon Musk, the CEO of Tesla (NASDAQ:TSLA), to rescue the struggling solar energy company, which is saddled with enormous losses and a negative cash flow. Musk also serves as the chairman of Solar City.
On the New York Stock Exchange, declining issues outnumbered advancing ones by a 1,753-1,234 margin.