Fisher & Paykel Healthcare fell 2.7 per cent to $15.20. On Monday, it warned the cost of contesting the latest patent allegations from rival ResMed will cut annual earnings by as much as $10m in a far-ranging dispute across multiple jurisdictions.
"It's just part of doing business from here on in, basically," Wilson said.
"Fisher & Paykel is fortunate it's not the biggest part of their business, it's not as much of a threat as if it was infringing around the hospital part of their business. They had a really strong run and this has brought it back to earth a bit."
A2 Milk Co fell 3.3 per cent to $12.40 and Auckland International Airport dropped 1.9 per cent to $6.99.
Chorus was the best performer, up 2.3 per cent to $4.83, while Arvida Group rose 2.3 per cent to $1.35 and Metlifecare gained 1.9 per cent to $6.40.
NZFunds' Wilson said much of the focus today had been off-market, with both Steel & Tube Holdings and Oceania Healthcare in trading halts.
Steel & Tube was frozen at $1.23 as it ran a $17.8m shortfall bookbuild following its deeply discounted 1-for-1.9 pro rata rights offer, where shareholders bought about $42.3m of new shares at $1.05.
Oceania Healthcare was stopped at $1.14 as cornerstone shareholder Macquarie Group began selling down some of its shares. Macquarie intends to sell up to 95 million shares at 79 cents, representing 15.6 per cent of the company, and only part of the 57.2 per cent stake it owns. The smaller stake means the Macquarie entity will no longer be able to control the appointment of any directors to the board.