Claxton, the first-round leader, is at 8-under 134 on the El Camaleon course with Summerhays, who had 65, and Owen who carded his second consecutive 67.
Chris Stroud was a stroke back after 66, and Robert Allenby, Kevin Stadler and Richard S. Johnson followed at 6 under. Allenby shot 67, Stadler 68, and Johnson 66.
Claxton, the 30-year-old former Auburn player making his fifth career start on the PGA Tour, had four birdies and one bogey.
“The wind was a little gustier today, but I’ve just kind of had good control over my ball,” Claxton said. “I certainly had a couple of good breaks here and there and putted the ball well. I’m just doing all the things you do when you’re playing well.”
Summerhays had seven birdies and a bogey. The 28-year-old former Brigham Young player made only eight cuts in 29 PGA Tour starts last season.
“I drove the ball perfectly, pretty much,” Summerhays said. “I hit it really solid into the wind. It’s a tough driving golf course.”
Owen had five birdies and one bogey. The 40-year-old won the European Tour’s 2003 British Masters.
LPGA TOUR: In Singapore, Katie Futcher and Jenny Shin shot 5-under-par 67 in the HSBC Women’s Champions to join first-round leader Angela Stanford at the top of the leaderboard.
Futcher and Shin both had six birdies and one bogey to reach 8-under 136 and tie Stanford, who had 70, on a day temperatures reached the low 90s.
Stanford started the day with a two-shot lead, but admitted feeling fatigued after her opening 66.
South Korea’s Hee Young Park (68), compatriot Na Yeon Choi (71) and Japan’s Ai Miyazato (70) were tied three shots back at 5-under at Tanah Merah Country Club.
World No. 1 Yani Tseng struggled to 72 and is tied for 20th at 1-under.
Michelle Wie shot 81 and was 24 shots behind.