The major stock indexes fell more than 3.5% on Monday, as retail investors sold into the close. Ben Willis, Head Trader at Princeton Securities Group, said ETF investors were getting out of their positions late in the day, which accounted for a messy close. 'A bullish indicator is that generally when retail investors panic like that, that's your time to buy,' said Willis, who cautioned it is too soon to say whether retail investors are done selling. Willis said the market recovered from steep early losses on a market rumor that China would cut interest rates overnight, before selling off again in very heavy volume. Willis said the U.S. stock market will continue to be driven by fears of a Chinese slowdown, but he believes the correction has happened. He also discussed Apple (AAPL) CEO Tim Cook’s email to Jim Cramer, Portfolio Manager of Action Alerts PLUS.