Congress has pounded one more nail in the coffin of traditional pensions — and it did not have to happen.

In one of the most misguided retirement policy moves in recent memory, the Bipartisan Budget Act of 2015 signed last week by President Obama increases the odds that more pension plan sponsors will stop offering defined benefit pensions.

The law imposes a huge increase in the insurance premiums paid by single-employer plan sponsors to the Pension Benefit Guaranty Corporation (PBGC), the private-sector pension insurer.

PBGC did not request the increase, an agency official confirmed. But as PBGC premiums are recorded in the federal budget as revenue, the premium hike added about $4 billion from 2016 through 2025 and helped reduce the net price tag of the budget act.

Adding insult to injury, Congress did not increase funding for multi-employer pension funds — even though it is in much worse financial shape than PBGC's single-employer program; multi-employer premiums are not counted as revenue in the federal budget.

All this sounds like the typical Washington budget gimmickry — until you consider the very real potential consequence that even more companies will seek to terminate their plans.

Already, the availability of defined benefit pensions has plunged in the private sector to 20 percent of Fortune 500 companies, compared with 59 percent in 1998.

The PBGC notes that the number of large, fully funded plans that terminated their defined benefit plans rose in the past year, and that it expects the trend to gather strength. PBGC premiums had not been a big factor behind that ongoing shift — until now.

The new budget boosts premium rates paid into the PBGC insurance fund by more than 40 percent over the next four years — and that comes on top of earlier increases approved in an earlier 2013 budget deal.

PBGC does have financial challenges. The agency says the single-employer program's deficit rose to $24.1 billion last year, up from $19.3 billion reported in 2014.

But even before the premium hikes enacted in the budget legislation, PBGC's long-range projections showed that the program's finances are likely to improve and that it is "highly unlikely" to run out of funds in the next 10 years.

That forecast did not deter Congress. It now has its $4 billion — but you may be left asking: "Where's my pension?"

Mark Miller is a Reuters columnist.