Sorry, I couldn't find pricing data for that day. The closing price for the S&P 500 (GSPC) on January 17, 2020 was $3,329.62. It was up 0.2% for the day. The latest price is $6,010.65.
DATE
OPEN
HIGH
LOW
CLOSE
VOLUME
January 17 2020
$3,323.66
$3,329.88
$3,318.86
$3,329.62
3,698,170,000
Daily pricing data for the S&P 500 dates back to 12/30/1927, and may be incomplete.