Sorry, I couldn't find pricing data for that day. The closing price for the S&P 500 (GSPC) on January 3, 1986 was $210.88. It was up 0.6% for the day. The latest price is $5,923.75.
DATE
OPEN
HIGH
LOW
CLOSE
VOLUME
January 03 1986
$209.59
$210.88
$209.51
$210.88
105,000,000
Daily pricing data for the S&P 500 dates back to 12/30/1927, and may be incomplete.