Russia's prospects for a higher debt grade after entering the World Trade Organization may not materialize because of the country's investment climate and institutional weaknesses, rating companies said.

Standard & Poor's, whose BBB rating has a stable outlook, doesn't anticipate “any immediate impact from WTO accession,” said Kai Stukenbrock, director of sovereign ratings in Europe, the Middle East and Africa. Russia must tackle “institutional weaknesses” such as the rule of law and corruption to reap the full benefits from WTO entry, according to Dietmar Hornung, a senior credit analyst at Moody's Investors Service

Prime Minister Vladimir Putin, who plans to return to the Kremlin next May, has yet to take significant measures to diversify the economy by improving the rule of law and reducing the role of state monopolies, Moody's and S&P said. None of the three main rating agencies have upgraded Russia's debt score since the 2008-2009 global financial crisis.