Michael Bloomberg, former Mayor of New York City, speaks at CityLab Detroit, a global city summit, on October 29, 2018 in Detroit, Michigan.

A major GOP money group is getting ready to slam Mike Bloomberg with negative talking points if the billionaire Democrat makes a run for the White House in 2020.

America Rising, a super PAC whose targets have included Hillary Clinton, is preparing an opposition-research blitz against Bloomberg that would focus on a range of topics, from his close relationships with Wall Street executives to controversial comments he made about women.

It's a sign that Republican Party insiders are taking the prospect of a Bloomberg run seriously as President Donald Trump runs for re-election.

"If Bloomberg decides to run, he will be part of the America Rising 2020 Initiative. We have already begun opposition research, rapid response, and video tracking on a host of potential Democratic candidates including Bloomberg," Sarah Dolan, the PAC's chief spokeswoman, told CNBC.

Bloomberg told the Associated Press in an interview on Tuesday he will make his decision on running by early 2019. A spokesman for Bloomberg did not return a request for comment for this story.

Bloomberg joins a list of possible 2020 Democratic targets for America Rising, including former Vice President Joe Biden, Sen. Elizabeth Warren of Massachusetts, Sen. Cory Booker of New Jersey, Sen. Kamala Harris of California and New York Gov. Andrew Cuomo, among others.

The group hopes to drive a bigger wedge between the centrist, pro-business Bloomberg and the Democratic base.

"Within the Democratic primary that is increasingly shifting to the left, Bloomberg's cozy relationship with Wall Street and his record on crime, specifically stop and frisk, and his previous comments on women and issues of sexual harassment, will be pressed by his primary opponents and America Rising," Dolan said.

America Rising, which was founded in 2013, raised just over $990,000 during the 2018 election cycle and spent $601,000, according to the nonpartisan Center for Responsive Politics. The group raised and spent considerably more money in 2016, when Clinton ran against Trump. That year, America Rising poured $1.4 million into the election and raised $1.3 million through top Republican donors such as billionaire hedge-fund manager Paul Singer.

The super PAC is looking to play up some of Bloomberg's controversial statements about women, including his recent remarks to The New York Times about news anchor Charlie Rose and the #MeToo movement.

"The stuff I read about is disgraceful — I don't know how true all of it is," he told the newspaper in September. Rose, who has been accused of sexual misconduct, used to produce his PBS show from Bloomberg's offices.

America Rising also has at the ready excerpts of interviews Bloomberg gave in the 1990s before he became the mayor of New York.

"I like theater, dining and chasing women," he once said. "Let me put it this way: I am a single, straight billionaire in Manhattan. What do you think? It's a wet dream."

Bloomberg, however, has championed causes for women.

In September, he spoke at an event sponsored by EMILY's List, a political action committee dedicated to helping pro-choice women get elected into Congress, and defended women who have spoken out throughout the #MeToo movement.

"Thanks to so many women who have courageously spoken out, the Me Too movement has shone a spotlight on sexual assault, abuse, and harassment – that, disgracefully, society has tolerated for a very long time," he said at the time.

He also spent millions supporting women running for office during the past election.

America Rising also wants to put Bloomberg's ties to Wall Street under the microscope. They plan to home in on his criticism of how the financial crisis was handled under Presidents George W. Bush and Barack Obama.

"It's a cheap shot to be able to go after the banks," he told Bloomberg TV in 2014.