Most straightforward way to foretell an S&P 500 top will be by observing massive divergence in MACD and RSI. Use weekly chart for better visibility. This happened in the 2000 peak and the 2007 peak. My prediction is that we have quite some time to go before S&P 500 turns bear. We will need to see a lot more obvious divergence (and volatility) before this happens. Also pay attention to NYSE Margin Debt as it should peak (leading indicator) before S&P 500 peaks.