#1 King Corbin (10.3%)
King Corbin engaged in a feud with Roman Reigns on WWE SmackDown in late 2019. The feud continued for weeks on end, with Reigns defeating Corbin at the Royal Rumble PPV in a Falls Count Anywhere match. The same story followed at WWE Super ShowDown, where Reigns won a Steel Cage match against Corbin. Pushed as one of the biggest heels on the main roster, it isn't a surprise to see that Corbin has a bad win-loss record. He competed in a string of dark matches earlier this year, and it isn't a secret that these bouts usually end with the babyface winning to send the fans home happy.
Corbin also lost to Elias at WrestleMania 36. He failed to win the Men's Money In The Bank Ladder match at WWE Headquarters as well. Corbin has wrestled 29 matches in 2020 and has won only 3 of them. With 25 losses and a draw, Corbin holds the wort win-loss record of any WWE Superstar in 2020 so far.