This Software Stock Just Produced a Rule of 40 Score Nearly as High as Palantir's, and Its Valuation Is Much More Attractive

Palantir Technologies (NASDAQ: PLTR) CEO Alex Karp is fond of highlighting the company's Rule of 40 score. The Rule of 40 states that a healthy software company's year-over-year revenue growth percentage plus its operating margin must exceed 40. Palantir blew that benchmark away last quarter, producing a Rule of 40 score of 155.

Another software company is quietly producing a triple-digit Rule of 40 score as well. But while the market is rewarding Palantir with earnings and sales multiples far in excess of those of practically any other company of its size, the valuation for this other fast-growing software stock is much more tame. In fact, its forward price-to-earnings (P/E) sits below 19, less than the overall S&P 500's.

Here's why AppLovin (NASDAQ: APP) deserves a closer look.

Image source: Getty Images.

Can this software stock keep its triple-digit Rule of 40 score?

AppLovin is an adtech company that sets itself apart by charging advertisers only when ads convert. The catch is, advertisers have to turn over practically everything about ad placement and pricing to AppLovin's black box model. The company's Axon 2 models have driven a sharp acceleration in revenue over the last few years, as it has also expanded AppLovin's market beyond its original gaming niche.

Management has seen excellent progress in non-gaming revenue growth, and it launched a self-service platform in June, which should help accelerate onboarding and total revenue growth. Total non-gaming-related revenue in the second quarter exceeded the seasonally strong fourth quarter by 28%. However, weakness in gaming advertising, which still accounts for the vast majority of its revenue, led to a disappointing overall result -- total revenue grew 53% year over year last quarter, down from the 59% growth it posted in the first quarter.

The weakness stems from the timing of the latest upgrade in the Axon 2 models. At the same time, the company spent more on compute to train its models and on research and development to improve them further. Management says the model update is now live, the third quarter is off to a strong start, and the business is back on the trajectory it expects. With its strength in gaming and the expansive market beyond gaming, management sees the potential for long-term compound annual revenue growth of 30%.

What's more, the business's margin profile is incredible. Despite increased spending to improve the Axon 2 models, the company posted an operating margin of 78% last quarter. That makes its Rule of 40 score 131 for the quarter. Over the long run, sales and marketing may come down as a percentage of revenue due to the growing self-service platform and the scale of operations. However, management is likely to funnel more money into research and development to ensure Axon 2 maintains its advantage over the competition.

CFO Matt Stumpf noted that the company doesn't manage for margin, but focuses on EBITDA and free cash flow growth. If it can invest a dollar in improving its artificial intelligence models and get more than a dollar back in cash returns, it'll do it. That said, Stumpf expects the EBITDA margin to remain in the low-80% range over the long term. So, combined with 30% long-term revenue growth, AppLovin should maintain a triple-digit Rule of 40 score for the foreseeable future.

Why is the market paying so much more for Palantir stock?

Palantir shares trade for more than 100 times estimated earnings over the next year and more than 50 times estimated sales. That's an exceptional premium, suggesting the company's growth runway is massive.

In comparison, AppLovin's earnings and sales multiples of 19 and 13, respectively, suggest investors don't expect earnings growth to remain elevated over the long run.

To be sure, Palantir has a tremendous opportunity. Its total addressable market could expand from $335 billion this year to $1.4 trillion by 2033, according to select analyst estimates. Palantir could merely maintain its market penetration rate and grow revenue at a compound rate of 23%. Doubling its market penetration, well within reason, would double that average growth rate.

That said, the digital advertising market is expected to grow relatively quickly as well. Global spending could reach $662 billion this year and $1.7 trillion by 2033, according to Grand View Research. That's a compound annual growth rate of 14.3%, which supports AppLovin's estimate of 30% long-term growth as it takes share of the large non-gaming ad market.

But while Palantir faces few limitations to its growth, AppLovin's black-box ad platform will struggle to deliver exceptional results for advertisers if it saturates the market. More advertisers using the same algorithm makes it less effective. That sets an upper limit on AppLovin's market penetration.

Still, at just 19 times forward earnings, the stock looks underpriced relative to its potential, even with that limitation. The company should be able to deliver strong revenue growth at very high margins for years to come, and the market is heavily discounting that right now.

Adam Levy has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Palantir Technologies. The Motley Fool has a disclosure policy.