Everton are fighting a battle to keep hold of the likes of John Stones, Ross Barkley, Romelu Lukaku and Gerard Deulofeu.
The form of John Stones, Romelu Lukaku, Ross Barkley and Gerard Deulofeu has caught the eye this season, but Martinez has no intention of selling any of the quartet.
The Spaniard says that if Everton were to sell any of their key players, they would demand a big fee – and he has talked up the value of his current squad.
“We would be the richest team in the world,” Martinez said, when talking about whether he would sell his key players.
Stones and Barkley are considered two of England’s brightest prospects for the future, and they are expected to have a huge role to play for club and country in the years ahead.
Lukaku and Deulofeu, meanwhile, are two of the Premier League’s most dangerous attacking threats already – and they have key roles to play at Goodison Park, despite their tender years.
Keeping all four at the club will be tough for Everton, and Martinez admits that getting into the Champions League will be crucial for his side.
“There are two things that can keep a player happy," he added.
“One is that he’s got stimulation to become better and he can see that he’s growing every day and the other is to be in the best leagues and the best competitions; so you have to get into the Champions League. That’s the top and bottom of it.
“That’s why sometimes you have to set a season where everyone invests into the team and see where that can take you. That’s what we’re doing now.”
This season’s Premier League has looked more open than ever before, so Martinez may be aiming to gatecrash the top four.
At the moment the Toffees are six points away from the Champions League qualification spots, meaning that they have some catching up to do, if they are to make it into Europe’s premier competition.