Executives at Unum Group Corp. (NYSE:UNM) and MetLife Inc. (NYSE:MET) say their companies may need to increase the level of reserves supporting closed blocks of long-term care insurance (LTCI) business.

Securities analysts at Sterne Agee have discussed the LTCI reserve moves in investor day reports.

John Nadel, one of the analysts, writes in a note on Unum that Unum may increase the LTCI reserves it holders under Generally Accepted Accounting Principles (GAAP), or the accounting rules that apply to all public companies, by about $600 million to $800 million this quarter. That would increase Unum’s LTCI reserves by about 7.5 percent to 10 percent, to a total of $8 billion.

The main driver of the reserve increase is the persistence of very low long-term interest rates, Nadel says.

See also: Why is LTCI so hard to price?

Unum is assuming that interest rates will fall even more and take three to five years to return to the pre-charge level, Nadel says.

Nadel says Unum’s core businesses are doing well.

In a note on MetLife, Nadel, Wesley Carmichael and Michael Ward say that company may increase LTCI statutory reserves, or the reserves it holds under the state statutes that apply to insurance companies, by $600 million to $800 million, or 6 percent to 7 percent.