The ProShares Ultra S&P500 ETF offers 2X leverage on the S&P 500, making it a strong swing trading instrument but vulnerable to long-term decay. SSO's drift is marginally negative over both 1-month and 1-year periods, with decay driven mainly by beta-slippage and market volatility. SSO has outperformed SPY in long-term annualized return but lags on risk-adjusted returns due to higher volatility and negative drift.