WASHINGTON (AP) — Sen. Elizabeth Warren is proposing a so-called ultra-millionaire tax as she vies for the 2020 Democratic presidential nomination.

According to two economists advising her presidential campaign on the plan, the tax would hit an estimated 75,000 of the wealthiest American households.

The new tax plan released Thursday by the Massachusetts Democrat would impose a new 2 percent fee annually on American households' net worth greater than $50 million.

The overall new tax bill on wealthy households would rise to 3 percent for households on their net worth above $1 billion under Warren's plan.

Economists Emmanuel Saez and Gabriel Zucman of the University of California, Berkeley, project that the tax proposal would generate about $2.75 trillion over 10 years.

Warren opened an exploratory committee for the 2020 presidential race last month.