US equity indexes ended higher Monday as crude oil prices dropped after Iran-backed militant group Houthis reportedly ceded territory it captured in September.

* The Institute for Supply Management's US services index fell to 54.9 in September from 55.4 in August, compared with expectations for 55.0 in a survey compiled by Bloomberg.

* The S&P Global US services index rose to 58.8 in September from a 58.7 flash reading, up from the 56.5 reported in August, compared with expectations for no revision in a survey compiled by Bloomberg.

* November West Texas Intermediate crude oil fell $1.81 to settle at $89.30 per barrel, while December Brent crude, the global benchmark, was last seen down $1.95 at $100.30.

* Schneider Electric said it plans to acquire PTC (PTC) in an all-cash deal valued at $23.7 billion. Shares of PTC rose past 33%, the top gainer on the S&P 500.

* C.H. Robinson Worldwide (CHRW) shares fell nearly 11%, the worst performer on the S&P 500, after the company agreed to acquire RXO (RXO) in a cash-and-stock deal valued at $5.8 billion. RXO stock was up over 22%.