Pietro Recchia/SOPA Images/LightRocket via Getty Images Big Tech is contributing less to the S&P 500's gains, DataTrek Research noted. In the third quarter so far, those stocks account for 6% of the index's growth. That's as non-tech sectors are growing more prominent, with financials in the lead. Big Tech's hold on the S&P 500 is finally loosening, as other sectors strengthen their presence on the index, according to Nicholas Colas, cofounder of DataTrek Research.