NEW YORK -- Citigroup is offering no explanation for Tuesday's sudden resignation of the bank's CEO, Vikram Pandit.

But the Wall Street Journal says the move followed a clash with the company's board over strategy and performance at Citigroup's businesses.

Shareholders also have objected to Pandit's pay packages. He received $15 million last year.

There had been no hint of the move Monday, when the bank announced strong third-quarter earnings. The earnings report sent Citigroup's stock price to its highest level since early April.

One analyst says the departure is a clear sign of a "complete and unexpected break" between Pandit and the board. But Chris Whalen of Tangent Capital Partners says he doesn't think the change will bring a shift in strategic direction for the bank.

Pandit's replacement is Michael Corbat, who had been head of the bank's division in Europe, the Middle East and Africa.

Citi is the country's third-largest bank, with $1.9 trillion in assets.