The conference committee considering the pension bill will hold a vote on whether or not to include a set of tax provisions - know as "extenders" - in the pension bill being considered. By moving the extenders out of the pension bill, the GOP leadership hopes use the extenders as a "sweetener" for an estate tax reduction bill to garner the 60 votes needed overcome a filibuster. Bloomberg: Senate and House negotiators will hold a showdown vote today to decide whether to add tax breaks to a measure to overhaul the private U.S. pension system and how many airlines should get extra time to shore up their retirement plans. Wyoming Senator Michael Enzi, the Republican chairman of the Senate-House conference committee negotiating the issues since March, said lawmakers will vote at 6 p.m. tonight on the two issues, which have been the main roadblocks to agreement on the pension measure. [...] The House and Senate differ on whether to renew about two dozen breaks including a popular research credit in the pension measure or use them to attract votes for separate estate tax legislation. They've also been unable to agree on how many airlines will be given extra time to shore up their pension plans.