MightyRiverPower fell 0.6 percent to $2.37, Genesis Energy declined 1.4 percent to $1.80, and TrustPower decreased 0.7 percent to $7.05.
"The political landscape is a little more fluid with some of the polling looking not totally in National's favour," said Shane Solly, director at Harbour Asset Management. "This sector and utilities have benefited from National looking like being re-elected."
Solly said the big earnings day, which also included Freightways, meant trading was lighter than usual as analysts pored over the reports.
"In the reporting season to date it's been relatively solid. We've seen more companies with earnings meeting expectations and some modest upgrades," he said.
Shares of Freightways gained 4.5 percent to a six-week high of $5.12 after it lifted profit excluding one-time items by 12 percent to $43 million in the 12 months ended June 30.
Outside the NZX 50, Opus International Consultants dropped 6.6 percent to $1.70 after the engineering firm increased first-half profit 6 percent to $9.9 million, just shy of First NZ Capital's forecast $10 million.
A2 Milk Co led the benchmark lower, falling 3 percent to 65 cents. Retirement village operator Summerset Holdings fell 2.4 percent to $2.81. Rival Ryman Healthcare fell 1.2 percent to $7.66, and Metlifecare was unchanged at $4.28.
Spark, formerly Telecom, fell 2.1 percent to $2.82 and Fletcher Building increased 0.2 percent to $9.05.
Xero led gainers on the day, up 5.6 percent to $21.30. Shares of the software developer plunged to a 10-month low last week as investors questioned the company's US growth aspirations. Guinness Peat Group gained 1.7 percent to 60, having fallen 16 percent through the latter half of last week after saying it was still grappling with its UK pension liability.
Hallenstein Glasson was unchanged at $3.05 after the clothing chain warned annual profit fell 25 percent, with a stronger second half failing to turn around a weak first six months of the financial year.
Shares of Lateral Corp closed the day at 20 cents after the mobile payments firm joined the NZX's small-cap Alternative Market in a compliance listing.