LONDON (Reuters) - Growth in euro zone business activity stalled this month as a tepid expansion in the bloc's dominant services industry failed to offset a deeper downturn among manufacturers, a survey showed on Wednesday.

HCOB's preliminary composite Purchasing Managers' Index, compiled by S&P Global, dropped to 50.1 this month from June's 50.9, barely above the 50 mark that separates growth from contraction and defying expectations in a Reuters poll for an uptick to 51.1.

Expectations about the coming year waned again, suggesting business managers do not expect an imminent turnaround. The composite future output index registered a six-month low of 60.0 compared to June's 60.8.

A PMI covering the services sector fell to 51.9 this month from 52.8 versus a poll prediction for an increase to 53.0.

Services firms faced a steeper increase in input costs this month but raised their prices charged at a shallower rate. The output prices index eased to 53.2 from 53.5.