Bank of America has issued a warning to stock market investors, suggesting that the S&P 500 may be experiencing a correction. The warning is based on technical signals, with some comparisons being drawn to the dot-com era, and it appears that only a small portion of the S&P 500 is currently at new highs. The nature and implications of the warning are being described in varying terms, ranging from a blunt warning to a quiet signal, but overall it seems to be cautioning investors to be prepared for a potential stock market correction.