BTIG warns that Wall Street's relentless sector rotation is masking growing market fragility, with investors selling one group of stocks to buy another without meaningful overall gains. Currently, 22% of S&P 500 stocks are technically overbought, yet the index's own RSI sits at just 50.4. BTIG notes this divergence has been more extreme only once before, on April 19, 1999, while semiconductor stocks are now oversold and defensive sectors are increasingly stretched.