Parties and politicians preparing for the final months of the 2010 election cycle have opened a record number of joint fundraising committees to allow donors to write larger checks than individual campaigns can collect.

Campaigns have filed paperwork for more than 700 such groups since the beginning of 2009 — doubling the number that were active during the 2006 midterm elections, according to a CQ MoneyLine study of Federal Election Commission records.

Joint fundraising committees are separate entities set up by existing committees that allow them to fundraise together at joint events. Usually a campaign is limited to raising a maximum of $2,400 from one donor per election. But joint fundraising committees receive checks that are often in excess of $20,000 at major fundraising events. These large sums of money are pooled together through the committee, then divided among campaigns, parties and even politicians’ political action committees.

“Candidates are under more pressure than ever to raise money, and it may simply be that word is getting around that this is a simple way to do it,” said Paul Ryan, FEC program director and associate legal counsel for the Campaign Legal Center. “The only thing that a joint fundraising committee allows is for one check to be written instead of multiple checks.”

For example, House Minority Whip Eric Cantor’s joint committee, the Cantor Joint Fundraising Committee, has received the most money of any such group this cycle with more than $2.9 million in receipts. The bulk of the money came from 65 individual donations ranging from $10,000 to $50,200.

The Virginia Republican’s joint committee later divided this money into parcels, with $751,000 going to Cantor’s campaign; $336,000 going to Cantor’s leadership PAC called Every Republican Is Crucial; $557,000 going to the 7th District Republican Committee, which supports state and local candidates in his district; and $516,000 going to the National Republican Congressional Committee.

These conduit committees that allow campaigns to pool money from wealthy donors have reported receiving $45 million so far this cycle. But campaign finance experts expect much more money to be raised during the fever-pitched weeks before the election.

One of the common constructions of a joint fundraising committee is to raise money together from a campaign committee and the national party. This has led to joint committees sending nearly $9.5 million to national Republican Party committees and more than $5.7 million to national Democratic Party committees.

In these situations, the candidate often gets recognition with the national party for the money he or she has raised in “much the same way that bundlers get credit for how they raise contributions,” said Richard Hasen, a professor specializing in election law at Loyola Law School in Los Angeles. “It’s a way to gain stature in the party.”

Another common way that joint fundraising committees are set up is between a candidate and his or her PAC, essentially allowing all of the money to benefit one person. So far during the 2010 election cycle, joint committees have handed over more than $2.1 million to leadership PACs.

Under campaign finance laws, federal candidates can set up as many joint fundraising committees as they want. Sen. Barbara Boxer (D-Calif.), who is running for re-election this year, has at least three such committees that have collected more than $1 million each.

The 10 joint fundraising committees raising the most money in 2010 are:

1. Cantor Joint Fundraising Committee, $2,913,088, benefiting Cantor for Congress, Every Republican Is Crucial, the 7th District Republican Committee and the NRCC

2. Reid Victory Fund, $2,214,243, benefiting Friends For Harry Reid and the Nevada State Democratic Party

3. House Senate Victory Fund, $2,003,453, a joint committee of the Democratic Senatorial Campaign Committee and the Democratic Congressional Campaign Committee

4. Pennsylvania Senate Victory 2010, $1,935,400, by the DSCC and Citizens for Arlen Specter

5. California Victory 2010, $1,760,051, benefiting Friends of Barbara Boxer and the Democratic National Committee

6. California Senate 2010, $1,664,337, supporting Friends of Barbara Boxer, the DSCC and the Democratic State Central Committee of California Federal

7. U.S. Senate Victory Committee, $1,240,908, benefiting Friends of Kelly Ayotte, Friends of Roy Blunt, Jane Norton for Colorado, the Portman for Senate Committee, Marco Rubio for U.S. Senate, Simmons for Senate and the Toomey for Senate Committee

8. Senate-House Dinner 2009, $1,105,224, a joint effort of the NRCC and the National Republican Senatorial Committee

9. Boxer Victory Fund, $1,058,241, supporting Friends of Barbara Boxer and the DSCC

10. U.S. Senate Victory Committee 2010, $1,035,727, benefiting Boozman for Arkansas, Dan Coats for Indiana, Carly for California, the Portman for Senate Committee, Rossi for Senate, Marco Rubio for U.S. Senate and the Toomey for Senate Committee