Outside groups have been and currently are spending millions of dollars in attempts to stop Republican presidential front runner Donald Trump from becoming the Party’s presidential nominee.

He is a billionaire who took over the business of his father, expanded it very ambitiously and over many years, he has owned fine wines, jets, and exclusive golf resorts. He also has handed out loads of money to politicians from both parties.

There the similarities end between Donald Trump and Warren Stephens. As Trump is barreling toward the presidential nomination for the GOP, Stephens, who is an investment banker has emerged as one of the billionaires’ biggest deep pocket opponents with the GOP.

With Trump the leader in delegate count, his opponents in the Republican Party have become focused on not allowing him to win an outright majority that guarantees his nomination.

A group of three conservative groups that are not affiliated with any of the candidates have spend over $28 million against Trump, mostly on ads that are negative which have aired the last few weeks.

Thus far, the effort failed to dent popularity of the front runner. Warren Stephens and Jackson Steve his brother gave over $3.5 million between them in February to two groups showed Federal Elections Commission filings above $500,000 from last year.

The filings indicate that just one family more, the Ricketts from Omaha, Nebraska, is a bigger funder to the campaign to stop Trump, having donated over $5 million since the start of 2016.

Other supporters of this effort revealed in the FEC filings included Paul Singer a hedge fund manager who donated $1 million and San Francisco investor William Oberndorf who donated $500,000.

While front-runner Trump parlayed the exploits as a developer in New York into fame internationally and a career in reality TV, Stephens has cultivated a profile that is lower, but his family’s name for decades has been powerful across Arkansas.

According to a profile in 2012, his uncle Witt, a former salesman of Bibles, founded the investment bank back in 1933.

It now has over two dozen offices across the country as well as in Frankfurt and London.

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