Assured Guaranty Ltd. reported fourth-quarter 2017 operating income of $91 million, or 77 cents per share, down from $139 million, or $1.05 per share, in the prior-year period.

Net income for the quarter was $52 million, or 44 cents per share, compared with $197 million, or $1.49 per share, in the same period a year earlier.

The company's net income for the fourth quarter and full year 2017 included a $61 million provisional tax expense related to the estimated impact from the recently overhauled U.S. tax code.

Loss and loss adjustment expense for the quarter was $34 million, compared with $112 million a year earlier. The company's fourth-quarter 2017 expense was largely a result of an increase to loss reserves on Puerto Rico exposures, partially offset by a $105 million pretax gain on the settlement of a breach of representations and warranties claim.

Net earned premiums were $178 million, down from $236 million in the year-ago quarter. Economic development in the quarter was $15 million, primarily related to Puerto Rico exposures also partly offset by the settlement gain.

Non-GAAP adjusted book value per share was $77.74 as of Dec. 31, 2017, compared with $66.46 as of Dec. 31, 2016.

For full year 2017, Assured Guaranty recorded operating income of $661 million, or $5.41 per share, compared with $895 million, or $6.68 per share, in 2016.

Net income for 2017 was $730 million, or $5.96 per share, down from $881 million, or $6.56 per share, in the previous year.