As earnings season continues to unfold, Coca-Cola (KO 0.10%) added its own quarterly financials to the mix on Monday morning. The beverage company, which has been a major holding of Warren Buffett's Berkshire Hathaway since 1988, reported better-than-expected revenue and earnings per share for its first quarter. The results highlight the company's resilient business model during a time of uncertainty. In addition, they give some validation to Buffett's approach to investing.

Here's a closer look at Coca-Cola's first-quarter results -- and why Buffett owns the stock.

Resilient demand

Coca-Cola said its first-quarter revenue increased 5% year over year, with adjusted organic revenue rising 12% year over year. This put earnings per share at $0.72, up 12% from the same period last year. Adjusted earnings per share rose 5% year over year to $0.68, coming in well ahead of analysts' average forecast for earnings per share of $0.64. Revenue of $11 billion was also notably ahead of a consensus forecast for revenue of $10.8 billion.

This performance during an uncertain macroeconomic environment helps highlight the company's resilient business model. But the best case for Coca-Cola's continued strength even as consumers around the world are pressured in many parts of the world by inflation and higher interest rates is the company's volume growth. Unit sales volume growth increased 3% year over year during the first quarter of 2023. This is equal to the volume growth Coca-Cola saw in the same period last year.

Looking ahead to the rest of 2023, management remains confident in its business. Coca-Cola guided for adjusted organic revenue for the full year of 2023 to increase 7% to 8% year over year. This is in line with the view it laid out for investors when it reported fourth-quarter results earlier this year.

Coca-Cola's resilient business model is largely due to the company's powerful global brand and its efficient distribution of products to its end markets. Of course, the product's habitual consumption by consumers helps, too. These are factors that help build Coca-Cola's competitive advantage, or as Buffett calls it: a moat.

Investing in companies with predictable and enduring moats is fundamental to Buffett's investment philosophy. And there may be no better example of this than Coca-Cola. While Buffett's strategy may not be sexy, Coca-Cola's strong results during difficult times give credence to the famed investor's approach, which has helped him trounce the S&P 500's returns during his lifetime.

A cash cow

Another important aspect of Buffett's investment thesis in Coke is the strong cash flow the company generates. Indeed, Buffett looks for this in virtually every investment. Coke said in its first-quarter update that it expects to generate $9.5 billion in free cash flow this year. The company can then turn around and pay some of this cash out to shareholders. To this end, Coca-Cola has paid more than $7.6 billion to shareholders in dividends over the trailing 12 months. Further, Coca-Cola's dividend has grown steadily for decades. Indeed, Coca-Cola's increase this year marked its 61st consecutive year of dividend increases. This dividend history highlights company's ability to consistently generate cash. The company has been able to raise its dividend year in and year out despite wars, recessions, pandemics, periods of high interest rates and inflation, and more.

Coca-Cola's results show that Berkshire knows what it is doing with its 9.2% stake in the company.