The operator of brands such as Crowne Plaza, InterContinental, and Holiday Inn, said that revenue per available room grew 1.5% in the three months to the end of June, down from 2.7% in the first quarter and 2.5% a year earlier.
The Easter holiday, when there are fewer business travellers, fell in the second quarter this year from the first quarter last year.
Chief financial officer Paul Edgecliffe-Johnson said US oil producing states continued to be a slight drag. Results also showed negative growth in the Middle East.
IHG stock, which has gained over 20%, fell by over 4% at one stage. Hoteliers last year saw attacks in Europe hurt demand, but Mr Edgecliffe-Johnson said IHG had seen no impact from attacks in London and France this year.
“In a way, our guests around the world have had to get used to the frequency of attacks and they have become very resilient,” he said.
Boosted by a strong first quarter, the group posted an 7% rise in six-month underlying operating profit to $365m (€309m) and said it remained confident in the 2017 outlook.
IHG has reduced its ownership of hotels to expand via a cheaper fee model, under which it franchises and manages hotels, and focused on business customers to head off the challenge from the likes of Airbnb. It is launching a midscale brand in the US.