Merchants work on the New York Stock Change in New York, america, March 16, 2020.Michael Nagle | Xinhua Information Company | Getty Pictures(This story is for CNBC PRO subscribers solely.)A handful of tech names have led the market’s rebound for the reason that coronavirus-induced sell-off in March, and as these corporations grow to be an ever bigger share of the general market, some buyers have began to sound the alarm over potential dangers.”Issues of one other expertise bubble are rising,” mentioned Keith Lerner, chief market strategist at SunTrust, in a current observe to shoppers. “There may be additionally rising focus threat, with the highest 5 stocks now accounting for 22% of the S&P 500 Index.”