British multi-utility company National Grid PLC's underlying operating profit rose 4% year over year as the company's U.S. business posted strong financial and operational results.

Profit attributable to equity shareholders was £3.55 billion, or £1.02 per share, for the year that ended March 31, 2018, down from £7.80 billion, or £2.06 per share, in the year ended March 31, 2017.

The company reported an underlying operating profit of £3.50 billion for the year, up 4% from £3.38 billion in the previous year. Underlying operating profit of the company's U.S. regulated business rose 13% to £1.70 billion from £1.51 billion in the previous year.

The company's U.K. electricity transmission business reported an underlying operating profit of £1.06 billion, down 15% from £1.24 billion in the previous year. Underlying operating profit of the U.K. gas transmission business increased 12% year over year to £505 million from £449 million.

The company said its annual asset growth was 6% in the year, up from 5% in the previous year.

"Looking ahead, National Grid expects growth at the top end of the 5%-7% range for the medium term, and at least 7% in the near term, which we will deliver with continued capital discipline and improved efficiency across the Group," said John Pettigrew, CEO of National Grid.