Scratching your head over how US stocks are showing gains while unemployment soars? This FT explainer breaks down why you should exercise some caution in assessing the health of the US economy while the S&P 500 surges. Much of stock market recovery seen in recent months is attributable to localized gains in the tech and healthcare sectors, huge central bank stimulus, and widespread optimism that the economy will rebound quickly after the lockdown restrictions are lifted (watch runtime 2:37).