S&P 500 adds Quanta Services, drops Ingersoll-Rand

NEW YORK, June 4 (Reuters) - Standard & Poor's on Thursday said Quanta Services Inc (PWR.N), a provider of specialty contracting services, will replace Ingersoll-Rand Co (IR.N) in its flagship S&P 500 stock index .SPX after the close of trading on a date to be announced.

Ingersoll, an industrial conglomerate, is leaving the index because it is moving its place of incorporation to Ireland, making it ineligible for inclusion, S&P said.

Shares of companies joining the S&P 500 often rise because many portfolio managers try to track the index, and must buy shares of companies that enter it.

Quanta shares rose $1.06 to $24.74 after-hours within minutes of the S&P announcement, after rising 77 cents to $23.68 in regular trading. The company is based in Houston. (Reporting by Jonathan Stempel; Editing Bernard Orr)