The rating agency Standard & Poor's (S&P) on Wednesday downgraded sovereign debt ratings of Saudi Arabia, Brazil, Kazakhstan, Bahrain and Oman. The agency said that the reason is falling oil prices. Saudi Arabia's rating was lowered to A- stable from A negative. Brazil's rating was cut to BB from BB . Bahrain's rating was downgraded BB from BBB-, Oman's rating to BBB- stable from BBB negative, while Kazakhstan's rating to BBB- from BBB negative.