Bruce Burnworth used to clip coupons and look for deals before his investment in Tesla Inc. made him a millionaire.
He is part of a widening class of affluent Americans who are doubling, or even tripling, down on this year’s highflying stock market. The S&P 500 has soared 66% since bottoming in March in the early days of the Covid-19 pandemic, while dozens of individual stocks, like Tesla, have surged even higher.