Warren Buffett timed his Apple stock sale to perfection. What’s next?

When Warren Buffett hosts “Woodstock for Capitalists” 11 days from now, he’ll have replaced one pesky question with another.

Berkshire Hathaway is sitting on more cash than any company in history, including its own, at about $318 billion. Much of it piled up the old-fashioned way, in a steady stream from the conglomerate’s subsidiaries and investments. That got turbocharged last year when Berkshire sold a large chunk of its stock portfolio—notably shares of Apple.

The gigantic bet dating to 2016 had made some investors nervous. Now that the iPhone maker has lost $1 trillion, or a quarter of its value, since its December peak, Buffett looks prescient.

But is his massive cash-hoard part of a grand plan to swoop in and buy stocks cheaply now that a possible bear market looms? And does Buffett anticipate tariff-induced chaos getting so bad that Berkshire can earn another bonanza bailing out blue chip companies, as he did during the financial crisis?

First it helps to understand why he probably sold. Berkshire’s large Apple stake, which it began building in 2016 to some investors’ discomfort, had become massive—probably the most lucrative single-stock investment of all time. Berkshire’s paper gains when it began selling were around $110 billion.

It wasn’t the first time Buffett’s investors second-guessed his bet on what already seemed like a fully priced stock. Between 1988 and 1994, Berkshire made what was then its largest ever portfolio investment in Coca-Cola. By 1998 it had appreciated tenfold, trading at 45 times earnings. Buffett said years later that he regretted not lightening his position.

“It was a really wonderful business that sold at a very silly price.”

He heaped similar praise on Apple and its chief executive, Tim Cook, but the Coke experience probably influenced his thinking.

“I would be surprised if it didn’t come to mind for him,” says Adam J. Mead, a New Hampshire money manager and Buffetologist who is the author of “The Complete Financial History of Berkshire Hathaway.”

With markets wobbling and a recession possible, Berkshire’s cash pile has reassured its investors, helping it beat the S&P 500 by nearly 25 percentage points this year. When and how will it be invested? That is complicated.

“His opportunity set is pretty small,” says investing newsletter writer Alex Morris, author of “Buffett And Munger Unscripted.” With the conglomerate’s market value over $1 trillion, it takes a lot to move the needle.

Back in 2009 Berkshire made its largest-ever acquisition, agreeing to pay $26 billion for Burlington Northern Santa Fe, then America’s largest railroad by revenue. Today that would be less than a tenth of his cash hoard and just 2.5% of Berkshire’s value.

Two possibilities Morris raises: Buying the remainder of longtime holdings Coca-Cola or American Express and taking them private, which would run around $280 billion or $130 billion, respectively.

What about the sort of lucrative lifelines Berkshire extended to blue chips Goldman Sachs, Bank of America and Dow Chemical during the financial crisis, should similar opportunities arise?

“They’d have to be significantly larger to make a dent,” says Morris.

One troubling interpretation of his cash hoard is that Buffett knows something about the tariff-hit economy we don’t. That is almost certainly true.

“He’s getting real-time information” through companies in his wide-ranging conglomerate, says Mead.

But it doesn’t necessarily mean he sees disaster ahead. It only tells us that the handful of securities it is worth his while to snap up—including Berkshire Hathaway stock—just aren’t priced right. And, with his Treasury bills at least yielding something now, he is getting paid to wait.

Buffett knew when to sell this time. Deciding when, and what, to buy has become much harder.

Write to Spencer Jakab at Spencer.Jakab@wsj.com