Even though the U.S. Chamber of Commerce has been among the most active outside groups trying to influence the midterm elections, the prominent business organization is likely to fall short of its ambitious spending goal of $75 million.

As of Monday, the chamber disclosed spending $32.4 million this cycle on electioneering and communications activities, the bulk of that in television advertising. Most of the political activity has occurred in the past month, with the chamber reporting to the Federal Election Commission that it has spent $20 million in key races since Oct. 5. That spending largely targeted Democratic incumbents and supported Republican challengers.

The chamber’s political action committee has also contributed $123,000 to federal candidates, political parties and leadership PACs. The vast majority of that money has gone to Republicans.

On top of the advertising spots, which are reported as electioneering and communications expenses to the FEC, the chamber has contributed almost $7.5 million to largely unregulated 527s that are involved in campaigns. The largest chunk of the chamber’s 527 contributions went to the Republican Governors Association, which has been aggressively campaigning for GOP candidates.

The chamber’s spending total will likely increase once final figures are reported after Tuesday’s elections.

Chamber spokesman J.P. Fielder said the group’s political efforts included more than advertising. “Our voter education activities encompass a variety of tactics beyond TV ads including grassroots, mailers and others,” he said in a statement. However, he did not provide a cost figure for those activities, nor would he give the chamber’s total campaign spending projection.

Fielder suggested that the chamber’s political efforts have been successful. “We feel that our strategy throughout this cycle, to keep this election focused on the economy and jobs, has put a number of pro-business candidates in a good position heading into Election Day,” he said.

The chamber has spent the most in hotly contested Senate races in Illinois, California, Colorado, New Hampshire, Pennsylvania, Washington, Kentucky and Wisconsin.

The chamber’s investment may not pay off in some of those races. It bet big in California, one of the most expensive media markets in the nation, spending $1.6 million in the past month trying to defeat incumbent Democratic Sen. Barbara Boxer. However, pre-election polls show her ahead of Republican opponent Carly Fiorina, the former CEO of Hewlett-Packard.

The group has also spent a half-million dollars since Oct. 5 in Connecticut to defeat Democrat Richard Blumenthal, who is poised to win his Senate race against Republican Linda McMahon.

On the other hand, the chamber spent $1 million in the past month to defeat Democratic Rep. Paul Hodes’ Senate bid in New Hampshire and Florida Gov. Charlie Crist’s independent bid in that state’s Senate race. Polls show that both men are likely to lose.

Election night will tell whether other chamber decisions paid off. Its most expensive advertising purchase in the past month was in Illinois, where it dropped almost $1.7 million to defeat Democrat Alexi Giannoulias, who is in a tight Senate race against Republican Rep. Mark Kirk. The group also spent $1.5 million on ads in Colorado during that period trying to defeat incumbent Democratic Sen. Michael Bennet, who is neck and neck with Republican Ken Buck.

The chamber, however, has not spent any money in the past month on the high-profile contest pitting Senate Majority Leader Harry Reid (D-Nev.) against Republican Sharron Angle, who is backed by the tea party.

Vulnerable House Democrats have also been targeted by the chamber, which spent the most — almost $550,000 in the past month — trying to unseat Rep. Dina Titus in Nevada.

The chamber’s other top House target was Rep. Tom Perriello of Virginia, who is considered among the most endangered Democratic incumbents this cycle and for whom President Barack Obama campaigned last week. The group spent $443,000 against Perriello in the past month.

Although the chamber generally supported Republicans, it spent $50,000 on behalf of Democratic Rep. Allen Boyd, who is in a competitive re-election race in Florida.

The chamber was the second-highest donor to 527s — tax-exempt organizations that are named for a section of the tax code which can raise unlimited funds for issue advocacy and political activities — in the current election cycle. It was eclipsed only by the American Federation of State, County and Municipal Employees, which contributed almost $7.9 million.

The top individual donor to 527s was Houston developer Bob Perry, who gave $6 million, much of it to the Republican Governors Association. Perry is a longtime GOP donor with ties to President George W. Bush’s political adviser, Karl Rove. Perry was one of the key donors to the Swift Boat Veterans for Truth, which spearheaded an advertising effort in 2004 to discredit the military service in Vietnam of the Democratic presidential contender, Sen. John Kerry (Mass.).

Another top GOP donor to 527s is Fred Eshelman, who founded Pharmaceutical Product Development and who gave $3.4 million to RightChange, a conservative group.