The insurance industry had an interesting 2017. Many insurers saw their investment returns grow as interest rates started to rise, but many also felt the impact of a particularly active and loss-inducing hurricane season.

Going forward, insurance stocks should generally benefit from the continuing rise in rates. Here are three profitable and fast-growing insurers that could make great additions to your portfolio now.

Insurance terms such as risk management and protection written in an array of hexagons.

Image source: Getty Images.

Company (Symbol)

Type of Insurance

Recent Stock Price

Dividend Yield

Progressive (NYSE:PGR)

Property-casualty, liability

$57.91

1.2%

Allstate (NYSE:ALL)

Property-casualty, liability, health

$104.02

1.4%

Employers Holdings (NYSE:EIG)

Workers' comp.

$43.30

1.4%

Data source: TD Ameritrade. Prices and dividend yields as of 1/22/18.

1. Progressive

Many Americans know Progressive for their commercials featuring a "name-your-own-price" method of buying auto insurance. In addition to its thriving auto insurance business, Progressive is the largest seller of motorcycle insurance in the U.S. and is also the majority owner of homeowners insurance company American Strategic Insurance (ASI). The company has 15.8 million personal policies in force, as well as about 640,000 commercial and 1.4 million property insurance policies.

Progressive's growth has been quite impressive in recent years. Through the first three quarters of 2017, the company had written 14% more premiums than in the same period in 2016, and it has increased its per-share net income by a staggering 56%.

Man kneeling and talking on the phone in front of crashed cars.

Image source: Getty Images.

In addition, Progressive ran a 5.8% underwriting margin during the period. Now, a profit margin of less than 6% may not sound great if you're not familiar with the insurance business, but consider this: Generally speaking, insurance companies aim to make the bulk of their money from investment income made on collected premiums waiting to be paid out for claims -- not on the premiums themselves. So, if an insurer makes a profit on underwriting in addition to its investment income, it's a sign of strong overall profitability.

Another way that insurers express this information is known as the combined ratio, which, in simple English, is the percentage of premiums paid out for claims and expenses. Progressive's combined ratio is 94.2 (100% minus the 5.8% underwriting profit), and anything under 100 indicates an underwriting profit.

On the other side, Progressive's investment portfolio has generated a yield of 4.2% through three quarters, but this was mainly fueled by equity returns. Fixed-income investments, which make up the bulk of most insurers' investments, are hindered by low interest rates but could see a big boost over the next few years if the Federal Reserve continues to raise rates as predicted.

The combination of a strong underwriting profit, growing investment income, and double-digit insurance premium growth could translate to excellent performance for Progressive in the years ahead.

2. Allstate

Allstate is the largest public property-casualty insurance company in the U.S., offering auto, homeowners, business, life, and other types of insurance. Allstate serves approximately 16 million households and currently has 78 million policies in force.

Like Progressive, Allstate operates at a strong underwriting profit -- its combined ratio is 95.2 through the first three quarters of 2017, despite nearly $2 billion of catastrophic losses due mainly to the active hurricane season. And the company has earned nice investment returns (4.9% year to date), but they have also been depressed because of low interest rates.

I like Allstate for the diversity of its operations, in addition to its profitability, as there are some interesting growth pathways for the company going forward. For example, Allstate's SquareTrade subsidiary, which was acquired in 2016, provides extended warranties for consumer electronics and appliances. Over the past year, the company's policies in force grew by a staggering 32%, and with the rapid evolution and adoption of new electronic devices, the business should have plenty of room to keep growing in the years ahead. Allstate Financial, Allstate Life, Allstate Benefits, and Allstate Annuities are all growing nicely, as well, which could also help drive revenue growth going forward.

3. Employers Holdings

The smallest and most specialized insurance company on this list, Employers Holdings, provides workers' compensation insurance, primarily to small businesses in low- to medium-hazard industries. The company has about 85,000 policies in force and operates in 36 states and D.C., although the majority (56%) of the company's premium income comes from California.

Among the top industries insured by Employers are restaurants, hotels, physician practices, retail stores, and schools, just to give you a sense of what is meant by a lower-risk industry. These types of businesses generally produce fewer workers' compensation claims, which makes it easier for Employers to keep its risk in check.

Like the other two companies mentioned here, Employers Holdings operates at a healthy underwriting profit. In fact, its most recent combined ratio of 92.7% is the best of the three. And with all but 7.6% of the investment portfolio held in fixed-income securities, it's fair to say that Employers could be a big beneficiary of rising interest rates, as well.

Matthew Frankel owns shares of Employers Holdings. The Motley Fool owns shares of Employers Holdings. The Motley Fool has a disclosure policy.