Hillary Clinton gives a thumbs-up as she takes the stage at her campaign rally in West Palm Beach, Fla., on March 15. (Carlos Barria/Reuters)

Priorities USA Action, the main super PAC backing Hillary Clinton's presidential bid, had $44.5 million in the bank at the beginning of March and an additional $49 million in commitments as it readied to flank the former secretary of state in a possible general-election showdown with Donald Trump.

The super PAC raised $4.9 million in February, including $2 million from Chicago media executive and major Democratic donor Fred Eychaner, new Federal Election Commission filings show. Former hedge fund executive Henry Laufer and his wife, Marsha, also gave $2 million. Among other donors last month was actor and activist Jane Fonda, who gave the super PAC $10,000.

Priorities' February fundraising total represented a drop from the previous month, when it brought in $9.6 million. But the group has secured an additional $49 million in commitments, officials said. That brings its total fundraising and pledges for the cycle to $104 million.

"Our continued fundraising success means Priorities will be well prepared to fight back early and often against Republican attacks, take on the eventual GOP nominee, no matter who it is, and draw a sharp contrast between Hillary and her opponent," spokesman Justin Barasky said in a statement.

Several pro-Clinton super PACs are already compiling research on Trump's career, and plan to put resources into polling, focus groups and forensic accounting through the spring.