According to reports, Jim Parsons, Johnny Galecki, and Kaley Cuoco negotiated their contracts for "The Big Bang Theory" back in 2014. When the actors went into talks with the networks' higher-ups, it earned them $1 million per episode for playing the roles of Sheldon, Leonard, and Penny, respectively.

The contract earned the three main leads at least $90 million each while Kunal Nayyar and Simon Helberg — who play Raj and Howard, respectively — also negotiated their contracts together in the same year which earned them $750,000 per episode until season 10 of "The Big Bang Theory."

On the other hand, Melissa Rauch (Amy Farrah Fowler) and Mayim Bialik (Bernadette Rostenkowski-Wolowitz) — who have only been promoted as series regulars at a later date — started out with $60,000 per episode back in 2013. However,both actresses are now being paid $100,000 per episode of "The Big Bang Theory."

Rumors are circulating that CBS may opt to remove Cuoco from the series altogether if it continues for an 11^th season. One reason cited by Game and Guide has revealed that Cuoco may want to leave "The Big Bang Theory" because she's getting tired of playing the same role for 10 seasons.

There are also reports that Cuoco is asking for another raise that the showrunners are not keen on granting. Some rumors also say that Cuoco is not too happy with the extended arc that the show is developing for Bernadette's pregnancy, leading her to rethink a contract renewal for "The Big Bang Theory." 

If the decision was left to the network, CBS president Glen Geller said that they are keen on continuing the series for as long as everyone is on board.

"We are very confident that everyone involved wants more Big Bang past Year 10. I know Warner Bros will make those deals... We'll put it on for as long as everyone wants Big Bang on the air. I hope it lasts forever," he said.