Key TakeawaysShares of payroll and HR software provider Paycom Software surged 21% on Thursday, posting the biggest gain in the S&P 500.Paycom exceeded third-quarter sales and profit estimates as the strong labor market boosted demand for the company's workforce management services.With Thursday's gain, Paycom shares moved back into positive territory for 2024. Paycom Software (PAYC) shares skyrocketed 21% on Thursday, posting the top daily performance in the S&P 500, after the payroll and human resources s ...