Sorry, I couldn't find pricing data for that day. The closing price for the S&P 500 (GSPC) on June 29, 2018 was $2,718.37. It was down 0.3% for the day. The latest price is $5,700.65.
DATE
OPEN
HIGH
LOW
CLOSE
VOLUME
June 29 2018
$2,727.13
$2,743.26
$2,718.03
$2,718.37
3,586,800,000
Daily pricing data for the S&P 500 dates back to 12/30/1927, and may be incomplete.