By Dan Weil The Bank of America’s Sell Side Indicator hasn’t been at this level for five years. While the S&P 500 index surged 8% in October, sentiment toward stocks dipped, as measured by Bank of America’s Sell Side Indicator (SSI). The Indicator tracks Wall Street strategists’ recommended equity allocation. The SSI slid to 52.8% in October, the lowest level since early 2017, from 53.58% in September. But the dip is actually good news for stocks, according to BofA. That’s because the SSI is a contrarian indicator. Historically, when the SSI was at current levels or lower, the subsequent 12-mo…