Sen. Ron Wyden (D-OR) is calling for a crackdown on life insurance, arguing that the wealthiest people are using certain plans to dodge billions of dollars in tax liability.

Wyden, who is the chairman of the powerful Senate Finance Committee, claims that private placement life insurance plans — which are only available to high earners and people with large net values — are a “buy, borrow, die” tax shelter for the ultra-wealthy. His office recently released a report detailing the plans.