When voters cast their ballots in January’s presidential nominating contests, they may not know the moneyed interests behind the attack ads run by shadowy outside groups trying to influence their votes, despite a Federal Election Commission deadline requiring many of them to disclose information next week.

Although FEC regulations suggest that groups making expenditures in New Hampshire’s Jan. 10 primary must file a pre-primary report on Dec. 29, it’s not clear how many of them will do so.

There are plenty of opportunities for these groups to avoid scrutiny until, in some cases, Jan. 31. The first four potentially pivotal contests of the Republican presidential nominating process in Iowa, New Hampshire, South Carolina and Florida may already be over before the public learns who's bankrolling some of the new entities that have sprung up in the wake of Citizens United, the Supreme Court's landmark 2010 ruling that gave corporations, unions and other special interests the right to spend unlimited sums to influence elections.

Some of these groups already have spent millions in early-voting states, but little is known about most of them. Those that are required to register with the Federal Election Commission don't have to reveal which candidate they are supporting or opposing until they begin making independent expenditures. (Those that qualify as 501(c)4 "social welfare" organizations under the U.S. tax code never have to register with the FEC or reveal their donors.) Presidential campaigns are legally barred from coordinating expenditures with Super PACs, and some candidates have denounced their activities. But many of the presidential Super PACs are led by former campaign staffers and political aides of the candidates (See chart below).

Of the 20 Super PACs that Sunlight has identified as playing in the 2012 presidential race, only five have so far have released any information about donors. And most of that information is six months old. While some committees may be required to reveal donors next week, they can avoid doing so if:

They are not spending in New Hampshire. Committees could spend millions in Iowa, where the first votes of the 2012 presidential campaign will be cast Jan. 3, and still not have to report donors because the FEC does not recognize the Hawkeye State's caucuses as an election.

They hold their fire until Thursday, Dec. 22. Books for the pre-primary reports close today, so committees that don't start spending in New Hampshire until tomorrow won't have to report donors until after the election.

They ask the FEC to change their filing frequency from quarterly to monthly, pushing their next disclosure deadline back to Jan. 31, when their year-end reports are due.

The latter tactic was recently employed by Restore Our Future, a pro-Romney Super PAC led by a campaign staffer from his 2008 run for president, which has reported raising more than any other Super PAC backing a presidential hopeful. Restore Our Future had been on a ‘quarterly’ filing schedule for most of its existence, meaning it would be required to file pre-primary reports for every state it was active in.

But Restore Our Future notified the FEC on Dec. 10 that it would be changing to a ‘monthly’ schedule. Under the commission's regulations, that means the pro-Romney group won't have to report donors until Jan. 31, the date Florida voters will head to the polls.

Other Super PACs potentially could follow Restore Our Future's lead. But according to one election law attorney, the FEC should not allow this filing status change to eviscerate disclosure, and the regulations do not say it has to.

“I don’t think the law should be interpreted so as to allow a PAC to change its reporting schedule in the midst of a reporting period. Allowing that would enable a PAC to evade important campaign finance disclosure requirements,” said Paul Ryan, an attorney at the Campaign Legal Center, which advocates for strong campaign finance laws and voting rights.

Ryan said he thinks Restore Our Future should still be expected to file its pre-primary reports, with all the contributor information for the period before it announced the change on Dec. 10.

“I think they should be filing a report unless the FEC has given some clear guidance on this that I’m not aware of,” he added.

Not doing so would deprive voters of information before elections, he said. “That’s when it most effectively serves the public interest in having a well-informed electorate, which is something the Supreme Court has repeatedly recognized as vitally important to our democracy.”

Plenty of money is being raised and spent on the presidential campaign by these outside groups. Make Us Great Again, Inc., one of the seven Super PACs that have popped up to support Texas Gov. Rick Perry, has reported about $2.4 million in independent expenditures. Our Destiny PAC, backing former Utah Gov. Jon Huntsman, has reported nearly $1.9 million in such spending, and has targeted New Hampshire.

Yet, aside from news reports revealing possible contributors, the most recent information about donors to any of the active groups came in July, when mid-year reports were filed. The only Super PAC backing a presidential hopeful to release more recent donor information, Veterans for Rick Perry, did so because it folded.

FEC rules allow for this disclosure lag. In election years, those groups would have to file reports quarterly. However, during off years, the FEC allows them to file every six months.

Below is a chart of the 20 presidential Super PACs, including the names of the people involved who have known relationships with the candidates the outside groups are assisting. The table also includes the money raised and spent on independent expenditures that have been reported to the FEC at the time this article was published. One group that has been publicly identified with GOP contender Newt Gingrich, Spirit of America Solutions, is not included because, according to its executive director Michael Phillips, it has not committed to supporting him in the GOP primaries but would do so if he becomes the nominee.

Know about some presidential Super PACs, or some connections between Super PACs and candidates that we missed? Please email us and help shed some sunlight on the 2012 presidential race.

Ryan Sibley contributed reporting