Focus on the pronunciation of vested interest
English definition of “vested interest”
› a strong reason for supporting a particular action which will give you a personal or financial advantage: a vested interest in sth Leaks about a possible merger were traced back to the companies with a vested interest in the deal. The majority faction has a vested interest in taking part in the election.
vested interests [plural] disapproving › people or organizations with a financial or personal advantage in a system, situation, etc., used especially when they refuse to allow changes to it that would cause them to lose this advantage: The bond market and other vested interests fought plans to tighten the tax loopholes. Strong vested interests can keep a counter-productive policy going almost indefinitely.