President Obama has called on Congress to approve increases in PBGC premiums, as well as to give the agency the direct authority to raise premiums. 

Also read: The PBGC's perfect storm 

The dramatic year-over-year increase in the MEP program's projected deficit is mainly related to the expected insolvency of two large plans with more than $26 billion in liabilities, as well as 14 smaller plans with combined liabilities of almost $9 billion.

"There is a minority of plans that do not appear able to work their way out of their problem on their own and are likely to run out of money," said a representative of the multiemployer program. "They represent the majority of the liability at PBGC."

PBGC officials declined to name the troubled MEPs in question.

In 2014, the PBGC paid out $97 million in financial assistance to 53 insolvent MEPs, covering approximately 52,000 retirees. 

The deficit in the multiemployer program stands at $42.4 billion, up from $8.3 billion last year.

All told, the multiemployer program holds less than $1.8 billion in assets. 

Officials said the MEP insurance program has enough money to provide assistance to failed plans for several years, but that in eight or so years, the plan stands a more than 50 percent chance of becoming insolvent.

PBGC also projected that, absent increases in premiums, the multiple employer plan stands a 90 percent chance of becoming insolvent by 2025. 

The projections are largely in line with estimates it released in June. 

The multiemployer program covers about 10.3 million participants, down slightly from the previous year, in about 1,425 plans, according to the annual report. 

In October, the PBGC announced 2015 premium increases for both single and multiemployer plans. Per-participant premiums will increase to $13 in the multiemployer plans. In single-employer plans, the flat rate will increase to $57 per participant, up from $49. 

PBGC officials on Monday would not address specific policy solutions, particularly those offered by the National Coordinating Committee for Multiemployer Plans in "Solutions Not Bailouts," which suggests amending ERISA to allow for a reduction in benefits for current retirees. That proposal is backed by business and some labor interests. 

While it has advocated raising premiums, the Obama administration has said that premiums must not be set so high as to spur employers to leave plans. 

"The process of how premiums are set will be a political one in part," a PBGC official predicted at a news conference Monday. 

Responding to Monday's news, the Partnership for Multiemployer Retirement Security, a business and labor initiative supporting MEP reforms, urged Congress to act quickly on the recommendations in "Solutions Not Bailouts."

"The PBGC report … underscores that time is of the essence and that fast action by Congress could mean the difference between insolvency and solvency for many of these at-risk plans," it said. 

It cited, as an example, the case of the troubled Central States Teamsters pension plan.

"With the tools contained in the Solutions Not Bailouts proposal, their actuaries project that the plan will survive and participants will receive approximately $72 billion in benefits over the next 50 years," the group said, adding:

"Without action, the Central States plan will pay out approximately $28 billion over the next 12 years before it is terminated and becomes a ward of the PBGC."

"Congress needs to act now, before the bill gets too big for anyone to pay."

Central States alone is facing an estimated exposure of $20 billion, it said.

The American Benefits Council also sounded the alarm.

"Today's announcement should be a wake-up call for lawmakers to take action to shore up the multiemployer system," its president, James A. Klein, said.

According to the PBGC, the deficit in the single-employer plan dropped significantly in the past year, as expected, owing to an improved economy and the flow of an additional $869 million in premiums. The program's deficit in 2014 was $19.3 billion, down from 2013's deficit of $27.4 billion. The program has about $88 billion in assets.

Officials do not expect the single-employer plan to run out of money.