The upcoming options expiration for the S&P 500 Index ($SPX) on December 20 is anticipated to be the largest in history, with a notable call-to-put ratio of 10:1. Key options levels include a Call Wall at 6100.0, Gamma Flip at 6038, and a Put Wall at 5900. Recent trading data shows the last four closes for $SPX at 6051, 6051, 6074, and 6050. The current market flows indicate a strong focus on the 6100 level for calls, while the 6000 level is attracting attention from puts. Additionally, the Gamma Open Interest six months out shows a CallGamma/PutGamma Ratio of 1.14 and a Gamma Flip at 6050. Analysts are closely monitoring these levels as they could influence market movements leading up to the options expiration.