BOSTON — FleetBoston Financial reported a fourth-quarter loss of $34 million, after Fleet Financial Group’s merger with BankBoston Corp., but said excluding merger-related costs, net income for the quarter was up $726 million.

Those earnings, at 76 cents per share, amounted to an increase of 17 percent over the fourth quarter of 1998, when the net income was $622 million, or 65 cents per share.

The merger cost the corporation $760 million during the fourth quarter, providing a net loss for the quarter of 5 cents per share.

For 1999, FleetBoston Financial earned a net income, including the merger-related costs, of $2 billion, or $2.10 per share.

That compares to $2.41 per share for 1998, including merger-related costs.

Total revenues were up $468 million, or 15 percent, from the fourth quarter of 1998, and $2 billion, or 17 percent, for the year.

The company’s chairman and chief executive officer, Terrence Murray, said, “Our continued strong results bear out the power of our diversified franchise and the momentum sustained during the integration of two great franchises.

“Our merger is very much on course,” Murray said.

Fleet’s takeover of BankBoston received regulatory clearance in September, making the united bank the eighth largest in the country.

Total assets on Dec. 31, 1999, were $190.7 billion, up $12.8 billion from a year earlier.