Williamson said the offer boosted demand for other retirement village and aged care operators.
Oceania Healthcare rose 5.1 per cent at $1.23 on a volume of 959,000 shares, more than twice its 90-day average of 443,000. It was the most traded stock on the day.
Arvida Group rose 4.1 per cent to $1.80, and Summerset Group was up 4.4 per cent at $8.35, both records for the retirement village operators. Ryman Healthcare increased 0.6 per cent to $16.10.
Restaurant Brands led the market higher. It reached a record $13.10 with just 5,096 shares traded, well down on its 42,000 average. The fast-food operator agreed to buy 70 KFC and Taco Bell stores in Southern California for US$73m ($110.4m).
Williamson said the company's aggressive expansion in recent years into Australia, Hawaii and now the mainland US had been impressive.
Port of Tauranga climbed 3.5 per cent to a record close $7.97, with 107,000 shares traded, just below its 116,000 average.
Freightways increased 1.6 per cent to $8.77. It said its long-serving chief financial officer Mark Royle will step down next year and be replaced by Air New Zealand executive Stephan Deschamps.
Trading was relatively quiet heading into the Christmas holiday, with no companies trading on volumes of more than a million shares.
Spark New Zealand declined 0.2 per cent to $4.40 on a volume of 931,000 shares. It typically trades on a volume of 3.1 million.
Tourism Holdings posted the day's biggest decline, down 2.4 per cent at $3.20 on a volume of 89,000 shares, less than its 128,000 average.
Outside the benchmark index, Cannasouth rose 1.7 per cent to 60 cents. It said it received resource consent for its joint venture cultivation centre in Waikato.
Moa Group was unchanged at 29.5 cents. The hospitality group and beer maker said director Craig Styris, an executive director at Pioneer Capital, stepped down from the board, effective immediately. Pioneer distributed its Moa holding to its own investors in September and is no longer considered a substantial shareholder.
Wellington Drive Technologies decreased 0.6 per cent to 17.1 cents. The company affirmed its 2019 earnings guidance range of $3.5m to $4m and said its preliminary 2020 forecast was for earnings of $4.5m.