There’s a reason they call him the Oracle of Omaha.

For decades now investors have pored over Warren Buffett’s annual letter to shareholders, hoping to soak up whatever wisdom they can from the business icon. Every year Buffett uses the letter to muse on economic cycles, as well as the perennial investing principles that have powered Berkshire Hathaway Inc. into an enterprise valued at almost $1 trillion.

But corporate boards and C-suites should also heed Buffett’s advice. His letter is full of lessons on how to run a company and manage your investors. Here are the big takeaways from this year:

Talk to your shareholders like they’re Bertie.  When Buffett crafts his report, he thinks of writing for Bertie, his 90-year-old kid sister. “Bertie, like most of you, understands many accounting terms, but she is not ready for a CPA exam,” he explains. “She follows business news – reading four newspapers daily – but doesn’t consider herself an economic expert.”

To be fair, many of Omaha, Nebraska-based Berkshire’s shareholders are probably not as up on the news as Bertie, or as savvy an investor. But most companies could use a reminder that they should strive to communicate with investors in plain English. It helps avoid the “optimism and syrupy mush” that Buffett says are endemic of investor-relations and communications consultants. And if a company can’t explain its business model clearly and concisely, that should probably be a red flag to investors.

There’s a lot of money to be made in doing nothing. This isn’t a new Buffett lesson — it’s a core tenet of value investing, and Buffett is famously a value guy. But he hit hard on the do-nothing theme this year, nodding several times to the beauty of being a bystander. Case in point: The day he first invested in the Dow Jones Industrial Average in 1942, the index fell below 100; today it’s around 39,000. “America has been a terrific country for investors,” he writes. “All they have to do is sit quietly, listening to no one.” As for Bertie, Buffett notes that she’s been made very rich by not making a single trade in 43 years.

Big rewards don’t always have to come with big risks. Silicon Valley startup culture has indoctrinated us with the belief that you don’t get the big payout unless you put everything on the line. Berkshire is just the antithesis. Buffett writes that the company is always prepared for “the time of an economic paralysis” and that “extreme fiscal conservatism is a corporate pledge.” It’s not a particularly sexy approach, but it somehow hasn’t hampered Berkshire in clinching the title of largest GAAP net worth recorded by any US company.

When you know your successor, publicly name the person. Too many companies treat succession planning like a state secret. But due to his age, Buffett has had to address it head-on, naming Greg Abel his heir in 2021. In his annual letter, Buffett reminded investors that Abel is “ready to be CEO Of Berkshire tomorrow.” It will be a big deal whenever Abel takes over, but Buffett has removed some of the mystery and surprise from the transition, quelling investor concerns. Making a CEO handoff as boring as possible should be the goal of every company.

It pays to bet on the US. In Buffett’s model of stakeholder capitalism, the US takes top billing. “While we emphasize treating our employees, communities and suppliers well — who wouldn’t wish to do so? — our allegiance will always be to our country and our shareholders,” he writes.

That’s a kind of patriotism that seems quaint today, but it has powered several of Berkshire’s biggest investments. The company now owns almost a third of Occidental Petroleum Corp., whose oil and gas and carbon-capture initiatives are “very much in our country’s interest,” he writes. “Occidental is doing the right things for both its country and its owners.”

Avoid rascals. When considering a potential investment, who is running the company is just as important to Buffett as its economics. He wants “able and trustworthy managers” — although he notes that this is often tough to discern, and he hasn’t always gotten it right. Here he quotes Hugh McCulloch, the first Comptroller of the United States, who warned national banks to “never deal with a rascal under the expectation that you can prevent him from cheating you.” Buffett writes, “Many bankers who thought they could ‘manage’ the rascal problem have learned the wisdom of Mr. McCulloch’s advice — and I have as well. People are not that easy to read. Sincerity and empathy can easily be faked. That is as true now as it was in 1863.”

That’s good advice not just for business, but for life.

Beth Kowitt is a Bloomberg Opinion columnist covering corporate America. She was previously a senior writer and editor at Fortune Magazine.