Moore, who clinched his fifth PGA Tour victory at the John Deere Classic three weeks ago, birdied two of his last four holes to finish level with fellow American Hahn, who hit 14 of 14 fairways for the first time on the U.S. circuit.
Reed was delighted with his form from tee to green in the second of the PGA Tour's four playoff events, but was left scratching his head after his putting frailty on the back nine.
"That first nine, I made the putts I was supposed to make and then all of a sudden I went to the back nine and I missed a short one on one for birdie, a short one on two for birdie and a short one on three for par," Reed, 26, told reporters.
"It was just one of those nines where you're hitting the ball pretty solid, you're just not quite making putts."
Being in contention for a second consecutive week did not, however, come as a surprise to Reed.
"With how I've been playing, I don't see how I couldn't be in contention every week," he said. "Now, it's a different question being in contention and closing them off. I am just kind of focusing on what I'm doing right now."
Reed's first-round 68 was matched by American world number three Jordan Spieth, Olympic gold medallist Justin Rose, British Open champion Henrik Stenson and U.S. Open winner Dustin Johnson among others.
Australian world number one Jason Day opened with a 70 while five-times major winner Phil Mickelson battled to a 75 that included a quadruple-bogey eight at the sixth where he twice failed to dislodge his ball from thick reeds close to water.
Moore was thrilled to be in the title hunt after piling up six birdies in a bogey-free display.
"Solid golf," the 33-year-old said. "I didn't do anything too crazy, drove it okay but hit some nice irons and gave myself some great opportunities.
"The few times that I was out of position, I hit a couple of great chip shots today to recover."
The top 70 players on the FedExCup points list after the Deutsche Bank advance to the Sep. 8-11 BMW Championship in Carmel, Indiana where the leading 30 will qualify for the Tour Championship finale in Atlanta two weeks later.
(Reporting by Mark Lamport-Stokes in Los Angeles; Editing by Frank Pingue and Andrew Both)
