The market's biggest stocks hold the largest share of the S&P 500 in 40 years as mega-cap tech returns swell

9:40am PDT - August 10th, 2020    nikola stock - Business Insider

REUTERS/Brendan McDermid

• Investors' rush to tech giants pushed weighting of the S&P 500's 10 biggest stocks to record highs.
• The companies took up roughly 29% of the index as of July 31, according to The Wall Street Journal, the largest shar…