Helped by a strong fourth quarter, the six active private mortgage insurers wrote 12% more business in 2025 over the prior year.

Between the third and fourth quarter, new insurance written grew by 4%, according to a report from Bose George of Keefe Bruyette & Woods. Typically, the last three months of the year are weaker than the middle six, but the sharp decline in interest rates helped drive origination volume during the period.

Among the six companies, three companies — Arch, National MI and Radian — reported NIW volume year-over-year gains in the range of 20%. But Essent Group did 3% less business versus the third quarter and the fourth quarter of 2024.

Even with those large share percentage increases at the competition, for the sixth consecutive quarter, MGIC was the most prolific mortgage insurer.

However, the private mortgage insurers continue to lose market share to the Federal Housing Administration program, George said earlier in February. He used insurance-in-force estimates for most of the MIs, as not all companies had reported yet.

Those estimates for the mortgage insurers put IIF down 0.5% versus the third quarter but up 0.9% year-over-year. But FHA grew by 2.3% quarter-to-quarter and 9.4% from the final three months of 2024.

Since the third quarter of 2022, the MIs share has been on the decline, with FHA holding the majority of risk since the middle of 2023.

George's estimates for IIF growth is 2% for this year and next, but the pace will remain below the Federal Housing Administration program as it will continue to benefit from affordability-related factors.