Among the bigger local decliners were A2 Milk Co, down 2.3 per cent at $10.30, and Ryman Healthcare, down 4.4 per cent at $11.85. Westpac Banking Corp, down 5.5 per cent at $28.08, led the declines.
"A lot of that is being led out of the Australian market," Williamson said.
"Both A2 and Ryman are widely held by Australian investors" and they have suffered with the weaker sentiment in that market, he said.
Spark New Zealand was the heaviest traded stock today with almost 5.4 million changing hands – twice the daily average the past three months. It was up 0.5 per cent at $4.11, a new closing high.
Williamson said it was a good outperformance, relative to the rest of the market, for one of the country's leading stocks.
The company last week announced it will move into its own sports content production and said it has the capability to go after all sport in New Zealand for its streaming service.
Other stocks to have more than a million shares traded today were Meridian Energy, down 1.8 per cent at $3.22, Contact Energy, down 1.2 per cent at $5.80, Fisher & Paykel Healthcare, down 2.5 per cent at $13.70, and Precinct Properties, unchanged at $1.43.
Port of Tauranga rose 0.4 per cent to $5.12. The company told investors today it is budgeting on another year of strong container and bulk cargo growth and has started planning for expansion of its container berth and optimisation of its container terminal.
Chemist and animal healthcare business Ebos Group rose 1.1 per cent to $20.94 on light volume. Almost 20,700 shares changed hands, less than a third of the daily average the past three months.
Infratil, which today reported a 19 per cent increase in half-year operating earnings and raised its full-year forecast, fell 1.3 per cent to $3.485.
Williamson said there is a lot of positive news across the company's investment portfolio, although imputation credits on the firm's dividends have fallen as the group's offshore earnings have increased.
Among the smaller players, brewer Moa Group rose 2.4 per cent to 42 cents after signalling strong sales growth will get it close to breaking even in the six months through March.