Fixed income revenues are rebounding at investment banks around the world. Yet the sales and trading boss at one of the market's leading banks can't help but sound a note of frustration that things aren't looking even better a decade on from the financial crisis.

That's not to suggest that Paco Ybarra, Citigroup's global head of markets and securities services, isn't happy with a start to the year that has been kind to most of the industry's biggest sales and trading teams. At Citi, fixed income and equity market revenues both posted double-digit gains in the first quarter compared to a year earlier.