Everton boss Roberto Martinez is delighted over their new £16 million deal with Chang.
But Martinez said their league finish - and whether they can secure European qualification - will have more bearing on his transfer plans.
"Obviously the sponsorship deal with Chang is a relationship which has been over 10 years and you don't get these relationships in Premier League clubs and we value that," he said.
"To be able to sign a new three-year deal is exciting for both parties but it doesn't change anything (on transfers).
"We are in that key moment of the campaign with 30 points to play for and every player is desperate to have a big say and that is the only thing that matters.
"Whatever happens in the summer will be the next step but many of the decisions will depend on how we do in the next 10 games so you can imagine the focus goes into those games."
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