The leadership of the stock rally in 2024 has broadened, but earnings growth still relies on a relatively small cohort of companies, Saira Malik, chief investment officer at Nuveen, said in a Monday note.

As of the end of last week, 75% of S&P 500 companies reporting third-quarter results had beaten consensus estimates, she noted – that’s below the S&P 500’s 5-year average of 77 %, but in line with its 10-year average of 75%, according to FactSet.

“But even as the U.S. stock market rally has expanded beyond large-cap technology companies to encompass a more diverse range of sectors and companies, blended earnings growth (a combination of reported earnings and estimates for those that have not yet been released) for the overall index remains highly concentrated: Removing only the four largest contributing companies would reduce the S&P 500’s third-quarter blended earnings growth rate from +3.4% to -0.1%,” she noted.