LIMRA says the past five years have shown a steady increase in the amount of buy-out activity in the first three quarters. So far this year 195 pensions have transferred risk through buyouts, compared to 159 for the same period last year. LIMRA says 13 insurance companies are now actively competing for business in the market.

About $1.3 billion sales were executed for the first three quarters of 2012, $1.45 billion in 2013, and about $1.5 billion in the first three quarters of 2013.

LIMRA says the fourth quarter is usually the most active time for buyout deals.

“Based on our tracking, we think fourth quarter and full-year sales in 2015 will finish strong,” said Michael Ericson, an analyst at LIMRA.

Years of low interest rates have strained defined benefit plan sponsors in several ways. Investment returns on the fixed-income portions of pension assets have been pressured by low yields. And low interest rates also increase the cost of future liabilities, negatively affecting funding levels.

Perhaps most affecting is the impact low interest rates have on how the Pension Benefit Guaranty Corp. estimates its future liabilities and deficits.

In its recently released annual report, PBGC said the single-employer deficit increased to $24.1 billion, up from last year’s reported $19.3 billion deficit.

The agency said the interest rate used to project the cost of future liabilities dropped 55 basis points to 2.8 percent, resulting in $4.7 billion in new costs to future liabilities, and $3.3 billion to the cost of accrued liabilities. The $4.1 billion in net premium income paid by sponsors—a record high—helped offset the costs of low interest rates.

Critics of PBGC and sponsor advocates question the legitimacy of how the agency’s actuaries project deficits and the cost of future liabilities.

Today’s historically low interest rates, which are applied to project future liabilities, dramatically and inaccurately increase the cost of liabilities and drive up PBGC’s deficits, which in turn rationalizes the argument that sponsors need to pay higher premiums, say critics.

Others also question why PBGC does not take into account the health of a sponsor’s overall balance sheet or credit rating when setting premiums. That means the healthiest companies that are least likely to default on pension obligations are regarded in the same light as companies of lower credit worthiness.

And other critics say sponsors of fully funded or even over-funded plans should be credited for their status.

President Obama recently authorized three more years of premium increases when he signed the bi-partisan budget bill into law.

The per-participant rate will increase incrementally to $78 by 2019. This year it was $57, and next year it will be $64.

The per-participant flat-rate premium was $49 in 2014, $35 in 2011, and $33 in 2008.

In a statement, LIMRA suggested years of premium increases have accelerated the de-risking market, and are expected to continue to do so.