Deutsche Bank’s plan to become “the last man standing” in investment banking in Europe is working, the bank said on Tuesday, reporting a 16 percent year-on-year increase in quarterly pretax income. Deutsche Bank faces an array of investigations that ranges from allegations of manipulating the Libor benchmark rate to unfairly favoring some investors in so-called dark pools and has already paid more than 5 billion euros over the past two years in settlements and fines.