J.J. Henry followed his course-record 60 with a 71 to join John Senden, Jeff Overton, Chesson Hadley and Jason Bohn at 11 under.
Bohn had a 64, Senden and Hadley shot 66, and Overton had a 68.
Defending champion Ryan Moore and Russell Knox were 10 under. Moore shot 63, and Knox had a 65.
Amy Yang overcame early jitters while playing in her home country, shooting a 5-under 67 to finish in a four-way tie for the lead after the first round of the KEB HanaBank Championship at Incheon, South Korea.
With friends and family in the gallery, Yang had six birdies, including five straight beginning at the fourth hole.
Bernhard Langer birdied the final hole for a 6-under 64 and a share of the first-round lead with Anders Forsbrand and Dick Mast in the Greater Hickory Classic at Conover, N.C. Langer and Forsbrand each had seven birdies and a bogey, and Mast had six birdies in a bogey-free round.
Webb Simpson -15
John Senden -11
Jeff Overton -11
Chesson Hadley -11
J.J. Henry -11
Jason Bohn -11
Daniel Summerhays -8
Mike Weir +1