Insurers that have been supporting portfolios with credit risk to counter low interest rates should consider diversifying with alternatives such as private equity, asset manager Conning & Co. said.

“We’re getting toward the end of the credit cycle, getting to an area where you have a lot of risk, then adding more,” Scott Daniels, head of investment advisory at the Hartford, Connecticut-based company, said in a phone interview Wednesday. “We don’t think that’s the best plan.”

Hedge funds, master limited partnerships and commercial mortgages should all be considered for the investment mix, Daniels said. Allstate Corp. and American International Group Inc. are among insurers that have allocated resources toward private equity and other alternatives while coping with low interest rates.

Book yields, a measure of income from bonds, are near historic lows, plunging from about 4.4 percent in 2007 to less than 3.2 percent last year, Conning said in a report being issued Thursday discussing trends for property-and-casualty insurers.

The asset manager, which oversaw $92 billion as of June 30, modeled scenarios of rising interest rates, high inflation, continued low rates or a stock market crash. In each situation, a hypothetical portfolio with 20 percent allocated toward alternative assets instead of equities or bonds was more valuable to insurers over a five-year period.

“There’s a very broad universe of assets out there beyond fixed income and public stock,” Daniels said. “It may seem intimidating or scary on a standalone basis, but when you look at adding a few percent to your current portfolios, you might end up in a better place in the long term.”