NEW YORK — It was nine months ago today that Mike Corbat was handed the reins of Citigroup and tasked with turning around the struggling banking giant. On Monday, the bank announced second-quarter results that beat Wall Street expectations and sent the stock higher — a result that analysts said was from the new CEO’s skill, rather than just luck.

Strong results from investment banking helped Citi’s April-to-June results, and the bank also benefited from setting aside less money for potential bad loans. Profit shot up 26 percent, after excluding an accounting gain, and revenue rose 8 percent.

That isn’t to say that Corbat’s path is without roadblocks.

On calls with analysts and reporters, Corbat and his chief financial officer, John Gerspach, were peppered with questions about a number of potential challenges. Among them: proposed new regulations that could require big banks to hold more capital, rising interest rates that could dampen demand for mortgages and a slowdown in growth in emerging market countries, on which Citigroup is heavily reliant.