Among the S&P 500’s 11 major industry sectors, the biggest gainer was S&P 500 healthcare, boosted by pharmaceutical companies. The healthcare rally had started in earnest on Tuesday after Pfizer and US President Donald Trump said that they had cut a deal. The S&P 500 tech sector provided another big boost for the benchmark index. The S&P 500 rose during each of the last six shutdowns, according to a note from Deutsche Bank. Corteva said it would separate its seed and pesticide businesses into separate publicly traded companies, sending its shares down sharply.