For the first two years, the rule only applies to network-affiliated stations in the top 50 markets, but after that, all stations will have to comply with the requirements.
The FCC says the rule is part of its effort to put more information online, and watchdog groups hope the rule will shed light on the big money behind political ad campaigns by making the data more accessible. The 2012 election is expected to see an influx of spending from outside groups such as super-PACs.
But the National Association of Broadcasters (NAB) filed suit in May to block the rules. The group argues the regulations are burdensome and that it's unfair to impose requirements on broadcast television that don't apply to its competitors in cable and satellite.
The broadcasters could ask a court to grant a stay, which would block the rules before they go into effect.
Republicans on the House Appropriations Committee briefly added a provision to a federal spending bill that would have stripped the FCC of its ability to enforce the rules, but the Republicans backed down when it became clear they wouldn't be able to enact the restriction in time to stop the regulations.