Warren Buffett had to work from his iPhone for days after lines went down at Berkshire Hathaway

• Warren Buffett slashed his Apple stake then found himself forced to work from his iPhone.
• The investor turned to the device after phone lines went down this week at Berkshire Hathaway HQ.

Warren Buffett may be cursing the universe for its wicked sense of humor.

The famed investor revealed during Berkshire Hathaway's annual shareholder meeting on Saturday that he'd slashed his Apple stake. Two days later, he walked into his company's headquarters to find the phone lines were down, forcing him to work from his iPhone.

"I don't know how to do much with it, but I do know how to answer calls," Buffett, 93, told The Omaha World-Herald on Wednesday when the local outage had not yet been resolved.

"I'm glad we didn't sell all of our Apple," he quipped.

Buffett famously spends his days analyzing companies and conversing on the phone, so the outage was a major headache for him — especially as he left his cellphone at home on Monday.

"We had this meeting that went over very well all weekend, and now to anybody who has phoned us in the last three days, they think we have gone out of business," Buffett joked to his hometown newspaper.

He was nodding to Berkshire cashing in 13% of its Apple stake for roughly $20 billion last quarter. At the end of December, the position was worth $174 billion and made up nearly half of Berkshire's $353 billion portfolio.

Berkshire's disposals, and an 11% drop in Apple's stock price, cut the holding's value to $135 billion, or 40% of the portfolio at the end of March.

Buffett is unabashedly old school and proudly frugal. Berkshire follows suit despite commanding a near-$900 billion valuation and ranking among the nation's 10 largest public companies.

For example, Berkshire's corporate homepage is a list of hyperlinks straight out of the 1990s:

Buffett's tech skepticism made his massive bet on Apple a surprise to many people. But the investor has pointed to the iPhone's immense appeal and how indispensable it is to users. He got a taste of just how much people rely on it this week.