Genesis Energy fell 2 per cent to $2.175 and Sky Network Television fell 1.9 per cent to $4.73.
The NZX 50 has fallen 1.5 per cent from its record high of August 23 and Williamson said a correction isn't surprising in the wake of earnings season.
"The reporting season has certainly been acceptable but expectations were extremely high," he said. The sell-off isn't likely to herald a major correction "because you keep coming back to the interest rate environment" where low interest rates make the stock market a stand out in terms of yield.
Auckland Airport rose 1.4 per cent to $7.30 after posting a 17 per cent gain in net profit as the nation's busiest gateway benefited from a boom in tourism and inbound migration that's driving passenger growth. It will pay a final dividend of 9c a share, fully imputed, making 17.5c for the year, a 19.9 per cent increase from 2015.
Air New Zealand rose 2.5 per cent to $2.275 as investors were lured to the airline's special dividend of 25c on top of an ordinary final dividend of 10c announced on Friday.
Among smaller companies, Intueri Education Group ended the day unchanged at 30c after posting a 43 per cent decline in first-half profit, on a gain in revenue that wasn't enough to offset the benefit of finance and other income in 2015, which wasn't repeated in the latest year.
Wellington Drive Technologies jumped 9.1 per cent to 12c after the maker of energy efficient motors for commercial refrigerators said revenue rose 38 per cent in the first half, driven by demand in the US and Canada ahead of the adoption of new regulatory standards next year.
Airwork Holdings was unchanged at $4.50 after the specialist aviation company delivered a 58 per cent boost in full-year profit to $24.6 million.