Investors should sell the S&P 500 above this key level as earnings defy expectations but 'economic ambiguity' persists, Bank of America says

• Sell the S&P 500 when it rises above 4,200, Bank of America's chief stock strategist said Friday. 
• "We stay bearish" as the US economy looks set to end 2023 with stress in the labor market and weak earnings. 
• The S&P 500 was edging toward logging a 20% gain from its bear-market low. 

The S&P 500 is edging close to a threshold that widely defines a bull market, but investors should consider ditching the large-cap stocks index at a key level as risk of an economic downturn looms, says Bank of America.