Standard & Poor's (S&P) today raised the foreign currency ratings of Tata Steel and Infosys Technologies.Under the revised ratings, Tata Steel has been upgraded to 'BBB' with stable outlook from 'BB' while Infosys has been moved up to 'BBB' with a stable outlook from 'BBB-', the agency said in a statement issued from Singapore.The revised ratings of the two companies is a part of the agency's revision of ten non-sovereign credit ratings in Asian countries including India, Indonesia, Philippines and Thailand.The revision is a result of review of transfer and convertibility risk in these markets, the statement said.According to the release, the upgradation of the ratings were undertaken as countries under political and economic stress are "considered less likely to restrict non-sovereign entities" increased access to the foreign exchange needed to service debt."This means that certain non-sovereign entities that are considered well insulated from direct and indirect sovereign risks may achieve a foreign currency rating that exceeds the sovereign foreign currency rating," the release added.The entities will tend to be those that demonstrate moderate leverage, strong freee cash fow generation and competitive business profile, the statement said.