Inflation has been on investors' minds for months now. For 10 consecutive months, year-over-year inflation, as measured by the consumer price index (CPI), has been above 5%. In March, the CPI was 8.5% higher than it was a year prior.

One stellar source of investment returns during periods of higher inflation is dividend stocks. According to research by Fidelity, dividends have accounted for 40% of the S&P 500's total returns since 1930. However, during the high-inflation decades of the 1940s and 1970s, dividends accounted for 65% and 71% of the index's total returns, respectively.

People standing in line at a bank ATM.

Image source: Getty Images.

Given that dividends deliver the goods for investors when inflation is high, Dividend Aristocrats can be solid stocks to hold during such times. To earn a place on that list, a company must increase its dividend payout annually for at least 25 consecutive years, and be a component of the S&P 500. The first requirement is a high hurdle to clear. However, that second one also keeps some great stocks off the list, despite their long streaks of payout hikes.

Three stellar dividend stocks that are flying under the aristocratic radar are RLI (RLI 1.71%), Old Republic International (ORI -0.10%), and United Bankshares (UBSI -0.78%).

RLI: A 46-year streak of dividend increases 

RLI is a specialty insurance company, writing select coverage in the property and casualty insurance lines. RLI has done a stellar job of underwriting profitable policies for decades now.  

One of the key metrics for gauging the quality of companies in the insurance industry is the combined ratio: the ratio of losses plus expenses to their total earned premiums. It's expressed as a percentage, and a ratio below 100 is desirable, as this means the insurer is collecting more premiums than it's paying out in claims and spending on expenses to run the business.

RLI has turned an underwriting profit for 26 consecutive years. During that time, its combined ratio averaged 88.4, and it never went above 100. In the insurance industry, this is a spectacular record. For reference, from 2000 through 2020, the average combined ratio for property and casualty insurers was 100.9.  

The company's ability to consistently underwrite policies profitably has allowed it to reward its shareholders. It has increased its dividend payout for 46 consecutive years, and at current share prices, delivers a decent yield of 0.87%.

A chart shows RLI's dividend increases over the past 20 years.

Source: RLI Corporation.

Not only that, but its payout ratio -- the share of total earnings paid out as dividends -- is just 53%. As such, it shouldn't have any problem maintaining and increasing its dividend. Over the past 10 years, RLI has delivered a total return (including dividends) of 421% versus the S&P 500's 258%.  

Old Republic International: A 41-year streak of dividend increases

Old Republic International is another insurer, working in a range of lines that includes aviation, commercial auto, general liability, and workers' compensation. The company also writes title insurance coverage used in property transactions to protect lenders or buyers from claims against a property's title.  

Old Republic, too, has done a stellar job of managing risk. In 14 of the past 15 years, its combined ratio has been below 100, and over that period, it has averaged a solid 96.  

A chart shows Old Republic's annual combined ratio since 2007.

Source: Old Republic International Corporation.

This has helped Old Republic crush the market over the last decade, delivering total returns of 365% versus the S&P 500's 282% returns. Old Republic has increased its dividend for 41 consecutive years, and at current share prices, it yields a solid 3.91%.

United Bankshares: A 48-year streak of dividend increases

United Bankshares is a regional bank focused on the mid-Atlantic states, with a strong presence in Virginia and Washington, D.C. It has achieved stellar growth through acquisitions. Since 1982, United Bankshares has bought 33 small regional banks. Its most recent acquisition deal, for Community Bankers Trust, closed in December and gave it additional branches throughout Virginia and Washington, D.C.

Efficiency ratio is a key metric when it comes to bank stocks. It measures operating expenses as a percentage of revenue -- and a 50% ratio is viewed as ideal. In 2021, United Bankshares put up a solid 57% efficiency ratio. For perspective, Bank of America and Wells Fargo put up efficiency ratios of 67% and 69% last year, respectively.

Rising interest rates should serve as a tailwind to United Bankshares' business. Last year, its net interest income was $743 million. Management projects that this will grow by between 7.7% and 10.4% to somewhere in the $800 million to $820 million range in 2022.  

The well-run bank has delivered dividend increases for 48 consecutive years due to its efficient operations and ability to identify strong acquisition opportunities over the years. And at current share prices, United Bankshares yields an excellent 4.14%.