NEW YORK — Wall Street shifted into reverse yesterday after a surprisingly weak retail sales report punctured investors' optimism about the economy.

The poor sales data, combined with a sharp drop in wholesale prices, came just as the corporate earnings season, usually a volatile time in the market, got under way.

Investors are already braced for bad earnings but are highly anxious about forecasts from companies that could indicate a weaker economy. Poor outlooks in the last earnings season in January derailed a 20 percent rally, and some fear the market's current five-week rally could be vulnerable as well.