On June 9, 2019, about 1555 MDT, United Airlines flight 401, a B737-924ER, N75436, experienced a tailstrike during landing at Denver International Airport (DEN), Denver, Colorado. There were no injuries to the 184 passengers and crew onboard. The airplane received substantial damage. The regularly scheduled domestic passenger flight was operating under 14 Code of Federal Regulations Part 121 from Reno International Airport (RNO), Reno, Nevada to DEN. The first officer (FO) was the pilot flying and the captain was the pilot monitoring. During short final, the FO noticed he was about 5 knots fast, and about 50 feet above the runway, started to slowly reduce power and start the landing flare. At touchdown the airplane bounced. The FO was about to advance throttles for a go-around, when the captain took control and continued the landing after a second bounce. During the post flight walk around, the flight crew observed that the lower aft fuselage had sustained damaged due to a tailstrike. Maintenance examination of the airplane found that the tailskid cartridge was compressed and there was substantial damage to the fuselage skin, frames, stringer clips and shear ties between fuselage station 827 to 907 and deformed stringers 27L and 27R.