Elizabeth Warren set to make 2020 presidential bid announcement next Saturday

Massachusetts senator proposing new wealth tax on millionaires and billionaires

Ms Warren speaks at January 2019 event in Iowa (Getty)

Massachusetts senator Elizabeth Warren is preparing to announce her candidacy for the 2020 presidential nomination next Saturday.

The prominent Democrat told supporters she will make a “BIG announcement” on 9 February and is widely expected to confirm her bid to unseat Donald Trump in the White House.

Ms Warren opened her presidential exploratory committee on New Year’s Eve, a move that made her the first high-profile sitting Democrat to enter the primary race.

Since then the senator has made trips to the early primary states of Iowa, New Hampshire and South Carolina. She also travelled to Puerto Rico, where she lambasted Mr Trump’s handling of Hurricane Maria relief and recovery efforts.

Ms Warren has been keen to assert her left-wing credentials, proposing a new 2 per cent tax on Americans whose net worth exceeds $50m (£38m). She has also suggested an additional 1 per cent levy on all billionaires.

“Billionaires like Howard Schultz and Michael Bloomberg want to keep a rigged system in place that benefits only them and their buddies,” she said last week.

Ms Warren has been joined in the early stages of primary campaigning by two fellow Democratic senators – Kirsten Gillibrand of New York and Kamala Harris of California.

Ms Harris recently caused a stir by pledging to scrap private health insurance. “Let’s eliminate all of that,” she said at a town hall event last week.

Other high-profile Democrats attracting media interest for possible 2020 runs included senators Bernie Sanders of Vermont and Cory Booker of New Jersey, former congressman Beto O’Rourke of Texas and former vice president Joe Biden.

The latest Politico/Morning Consult poll of Democrat voters showed Mr Biden ahead of the pack with 33 per cent of the vote.

Mr Sanders came in second, at 15 per cent, while Ms Harris came in third with 10 per cent. Ms Warren tied for fourth on 6 per cent.

Hillary Clinton’s former campaign manager John Podesta has dismissed speculation she is planning to launch another bid for the White House.