A political action committee backing Joe Biden's run for president has decided to invest in key Super Tuesday states as it picks up wealthy financiers while the former vice president attempts to mount a comeback in the primary race.

In the wake of Biden's successful debate and a well-received town hall in South Carolina, Unite the Country, a pro-Biden super PAC, has seen a surge in high dollar contributions from donors, one of its leaders told CNBC on Thursday. That's allowed the organization to invest in delegate-rich primaries that are set to take place on Super Tuesday, which is scheduled for March 3. The PAC will first target voters in Alabama and North Carolina with radio and digital ads.

"We've done very well in terms of the response with everything that's happened the last couple of weeks," Larry Rasky, the group's treasurer, told CNBC. "I would say things are starting to resonate with donors," he said, while pointing to Biden's debate and town hall performances as two reasons why donors are writing big checks to the PAC.

Rasky noted that a new poll in the key state of Florida, which shows Biden surging ahead of former New York mayor Mike Bloomberg, also peaked interest from donors. Florida's primary is March 17.

Bloomberg was, at first, slowly picking up some of Biden's top fundraisers, but since the former New York mayor's sluggish debate performance in Nevada two weeks ago, many of those people have decided to shift back into the former vice president's corner and give to the super PAC instead, according to a person with direct knowledge of the matter. The PAC has also started to acquire donors who were backing other primary contenders, this person noted.

Rasky would not say how much they are investing in the states or the amount they have raised but noted that they plan to focus more of their resources toward other Super Tuesday states.

Contrary to campaigns, super PACs can raise and spend an unlimited amount of money. In January, the pro-Biden PAC raised just over $4 million and spent $3.8 million, according to a Federal Election Commission filing. Their recent fundraising success was on the backs of business executives such as Silicon Valley investor Reid Hoffman, who contributed $500,000 last month, along with Blackstone executive, John McCormick.

The move by the super PAC comes as Biden is looking to pick up his first primary victory in South Carolina and trying to find momentum into next week's Super Tuesday contests. Sen. Bernie Sanders has become the Democratic primary front-runner after seeing victories in New Hampshire and Nevada.

The Biden campaign launched a separate six figure ad buy that will include broadcast spots in Alabama, Arkansas, Georgia, North Carolina, Tennessee, Texas and Virginia.

Biden is looking to overtake Sanders while he continues to lead in most polls and in the delegate count. A Real Clear Politics polling average has Biden in second behind Sanders, followed by Bloomberg, Sen. Elizabeth Warren and former South Bend Mayor Pete Buttigieg.