The ruble rallied for a second day, extending its biggest monthly increase on record, while Russian stocks and bonds gained as oil climbed and a cease-fire in Ukraine showed signs of holding. The currency rose 1.4 percent to 60.5470 per dollar by 12:08 p.m. in Moscow, taking its advance in February to 15 percent. Crude oil, Russia’s main export earner, is trading near its highest level this year, while Ukraine signaled that the cease-fire struck this month may endure. “Oil rallies and so does the ruble,” Dmitry Polevoy, chief economist for Russia and CIS at ING Groep NV in Moscow, said in e-mailed comments. “The geopolitical concerns have mostly been priced in, and to move the ruble considerably weaker, any new economic sanctions must be much tougher than what they are right now in reality, […]