The S&P 500 Index (SPX) and SPDR S&P 500 ETF Trust (SPY) have experienced significant volatility in recent trading sessions. The SPX saw notable movements in 0DTE (zero days to expiration) puts, with prices fluctuating dramatically within short periods. For instance, the SPX 5475 0DTE put rose from $6 to $26 in an hour. Another 0DTE put went from $2.80 at the Euroclose to $18 in 30 minutes. The SPY broke above $547.10 but then fell back below this level, indicating a volatile trading environment. Post-debate and pre-CPI (Consumer Price Index) data, SPX futures were down by 15 points, while SPY had key support levels at $542-$543 and resistance around $549. Traders are closely monitoring these levels, with some locking in profits and holding positions overnight. SPY must hold $544.65 and $546.41 for bullish momentum, with a key level at $539.44 if it falls below $543.