The ongoing bull market on Wall Street has defied traditional valuation metrics like the P/E ratio, PEG, and Earnings Yield, all of which signal overvaluation. Yet investor enthusiasm persists. This article introduces SIRRIPA—a forward-looking, risk-adjusted return metric derived from the Potential Payback Period (PPP)—as a more accurate tool. Tested on the S&P 500 and NVIDIA, SIRRIPA explains what conventional measures fail to: why stocks continue to rise despite appearing overvalued. Practitioners are invited to apply SIRRIPA across markets, using sensitivity analysis to ensure robust, data-driven insights.