Squishmallows are small plush toys that first launched in 2017. But it didn't take long to find its fanbase. According to The NPD Group, it was the best-selling toy of 2022, just five years after launch. And now, like Beanie Babies back in the 1990s, Squishmallows are getting their chance to headline Happy Meals from McDonald's.

Squishmallows Happy Meals launch on Dec. 26 in the U.S. nationwide. According to the company's USA Chief Marketing and Customer Experience Officer Tariq Hassan, McDonald's is "all about connecting our fans to culture, and Squishmallows are some of the hottest toys out there right now."

Since Squishmallows are popular right now, they'll undoubtedly be a hot holiday gift item this year as well.

Wouldn't it be great to invest in one of the "hottest toys out there" in Squishmallows? Well, investors don't need to wait for an initial public offering (IPO). As it turns out, you can already invest in Squishmallows because the brand sneakily went public years ago.

The surprise owner of Squishmallows

Squishmallows is a toy brand owned by toy company Jazwares. Jazwares was acquired by Alleghany Corporation in 2016. Then, in late 2022, Alleghany was acquired by none other than Warren Buffett's conglomerate Berkshire Hathaway (BRK.A -0.76%) (BRK.B -0.69%).

Therefore, you can invest in the Squishmallows brand by buying shares of Berkshire Hathaway. This is probably one of the last companies investors would expect to own a hot toy brand.

Then again, perhaps it's not so surprising that Berkshire Hathaway owns Squishmallows. After all, it's one of the most diverse businesses in the world, and it owns a wide smattering of the entire U.S. economy -- even toys.

Berkshire was a dying textile company when Buffett took over in the 1960's. The famed investor shrewdly saw the writing on the wall with textiles and began using the company's cash to buy other businesses. Now, it has business operations in insurance, restaurants, banks, energy, home builders, manufacturing, RVs, apparel, trucking, railroads, aviation, furniture, a valuable portfolio of stocks, and way, way more.

Berkshire Hathaway's market capitalization has increased almost 4,000% in the last 30 years, and it currently sits at $775 billion. Buffett attributes this phenomenal success to economic growth in general. He said, "America's dynamism has made a huge contribution to whatever success Berkshire has achieved." Elsewhere, he calls it the "American tailwind."

In many ways, therefore, investing in Berkshire Hathaway stock is much like betting on the whole U.S. economy by investing in an S&P 500 index fund. Whether investors chose Berkshire Hathaway stock or a collection of 500 of America's largest profitable companies, both will do well if the U.S. economy grows long-term. They benefit from the same tailwind.

But Berkshire Hathaway shareholders do have advantages over those who are invested in index funds. First, index funds have fees. And these fees guarantee that holders will perform slightly below average over the long term. There's no such fee for holding Berkshire stock.

Second, Berkshire Hathaway often repurchases its shares when it believes they're cheap, providing an extra boost to shareholders that index fund investors don't get.

Therefore, for investors looking for one of the safest stocks to buy, buying Berkshire Hathaway stock makes a lot of sense. With its market cap of $775 billion, it may not have the biggest upside out there. But it will likely perform admirably and consistently. And that could make it a good addition to a portfolio.

Oh yeah, and buying Berkshire Hathaway stock would give you an ownership stake in the hottest toy brand out there in Squishmallows, which might make this a slightly more fun idea than the market gives it credit for.