Russia’s currency extended a rally that’s taken it to the strongest level versus the dollar in four years, prompting a warning from one of President Vladimir Putin’s staunchest allies that the gains may be overdone. The ruble was stronger for a fifth day against the dollar, trading up 2% even after Russia on Monday loosened capital controls by reducing the amount of foreign currency exporters are required to convert. The Russian currency is by far the best performer globally this year with a gain of about 30% against the dollar. But its recovery since the invasion of Ukraine has been so rapid that economists are warning that the appreciation will batter budget revenue and hamper exporter competitiveness. “The ruble is strengthening at a crazy pace — We need to be careful not to overdo it,” Belarus President Alexander Lukashenko quipped at a meeting with Putin on Monday. […]