This market resolves to ‘YES’ if the S&P 500 closes up or down by 1% or more from October 23rd's closing price at 4 PM EST on October 24th. I will check the price using Google Finance.

EDIT: EDT not EST.

EDIT 2: 6805.82 would be 1% increase, 6671.72 would be 1% decrease. Currently edging the 1% increase.