Munger, 99, who passed away in late November, became vice chairman at the conglomerate in 1978. But well before then, he was providing crucial advice about running the company.

Buffett wrote that in 1965, Munger told him to “forget about ever buying another company like Berkshire,” but now that he had control of it, to “add to it wonderful businesses purchased at fair prices and give up buying fair businesses at wonderful prices.” 

Buffett followed his instructions.

After Munger joined Berkshire, he repeatedly “jerked me back to sanity when my old habits surfaced,” Buffett wrote. “Until his death, he continued in this role and together we, along with those who early on invested with us, ended up far better off than Charlie and I had ever dreamed possible.”

Aside from advising Buffett, Munger also made key decisions that turbocharged Berkshire’s success. His best call, he said a year ago, was an investment in the Chinese automaker BYD, which recently overtook Tesla in global sales of electric vehicles.

After backing BYD at Munger’s urging, Berkshire watched the value of its 2008 investment in the carmaker surge from $230 million to $9.5 billion 14 years later.

“I have never helped do anything at Berkshire that was as good as BYD,” Munger said during the annual meeting at the Daily Journal Corp., where he served as a director.

Munger was also known for his colorful language and candid remarks. He called Bitcoin “rat poison” and likened other cryptocurrencies to a type of “venereal disease.” Last year, he wrote in the Wall Street Journal that the federal government should ban the entire industry, describing a cryptocurrency as “a gambling contract with a nearly 100% edge for the house.” 

Buffett suggested that Munger’s role at Berkshire was far more important than most outsiders realized. 

“In reality, Charlie was the ‘architect’ of the present Berkshire, and I acted as the ‘general contractor’ to carry out the day-by-day construction of his vision,” Buffett wrote. 

He added, “Charlie never sought to take credit for his role as creator but instead let me take the bows and receive the accolades. In a way his relationship with me was part older brother, part loving father. Even when he knew he was right, he gave me the reins, and when I blundered he never—never—reminded me of my mistake.”

Later in the letter, Buffett bemoaned the dearth of worthwhile acquisition targets, noting that the mere “handful” of U.S. firms capable of moving the needle for Berkshire “have been endlessly picked over by us and by others.”

In the meantime, however, Berkshire’s cash hoard grew to a record $167.6 billion in the fourth quarter.