Bo Van Pelt, Colt Knost and Ryan Moore were also tied for the lead when the round concluded on Sunday morning. PGA Tour officials said it was the first six-player logjam after 54 holes since at least 1970, when statistic was first kept.
Couples finished 10 holes on Saturday, then birdied the par-4 12th on Sunday to join the leaders. Casey made three birdies after resuming his round, then bogeyed the 17th to slip back to 11-under, and Ogilvy birdied three of his first five holes to move up.
The tournament has been playing catch-up since high winds suspended play Thursday afternoon and wind gusts up to 35 mph were forecast for Sunday.