Oil price declines could dampen economic growth in Gulf states and weaken operating conditions in the corporate and infrastructure sectors, a major rating agency has warned.

“While the Gulf countries’ significant oil and gas reserves are key supports for their sovereign credit ratings, their economies’ concentration in the hydrocarbon sector is also a significant vulnerability, in our view,” said Standard & Poor’s Ratings Services in a report published on Monday.

The agency also revised Brent oil price at $85 a barrel for the rest of the year and $90 a barrel for 2015 and beyond. The assumption is very close to most of the Gulf states’ budget price for oil.

Brent crude was trading at $82.65 on Monday.

“A prolonged period of lower government revenue given GCC governments’ high infrastructure spending plans may push up sovereign and government-related entity capital market issuance and place a greater onus on the private sector to fund investments,” said the report.

The S&P warning came as Amin Nasser, senior vice president for upstream operations at Saudi Aramco, said on Monday that the recent fluctuations in oil prices would not threaten the company’s long-term supply commitments.

The agency added: “Lower government revenues may also result in increased government efforts to tackle energy subsidy reform. This, in turn, could hurt industries reliant on feedstock subsidies, such as petrochemicals.”

S&P also said: “By contrast, any change in energy subsidies to the power sector that would pave the way for more cost-reflective tariffs could improve the regulatory environment for infrastructure entities and weigh positively on their business risk profiles.”

It said: “We expect total credit in the GCC banking system to grow by about 10 percent annually in 2014 and 2015 as banks take advantage of growing economies, recovering corporate asset quality, and ample financing opportunities.”