Apple Inc.’s (AAPL) meteoric rise to $1 trillion in market capitalization has made retail and institutional investors richer. But one firm that may be benefiting the most is Berkshire Hathaway Inc. (BRK.B), the diversified conglomerate run by famed investor Warren Buffett.

Berkshire Hathaway is currently Apple’s second-biggest shareholder, owning about 5% of the company. With Apple’s market cap surpassing $1 trillion, making it the first U.S. company to reach that milestone, Berkshire’s coffers just got fuller. According to The Wall Street Journal, based on Apple’s closing stock price of $207.39 Thursday, Berkshire’s stake is worth close to $50 billion. And that's in a short time frame given that Berkshire purchased shares of Apple starting in the first quarter of 2016, when it bought $1 billion worth of the company at a price of $99.02, reported the WSJ, citing data from FactSet. That price is around half of what Apple’s stock is trading at currently. (See also: Apple Is a $1 Trillion Company. Now What?)

Berkshire Has Been Amassing Apple Shares Since 2016

Since 2016, Berkshire has amassed more of a stake in the iPhone maker, investing what the paper said was more than $30 billion from the first quarter of 2016 and the first quarter of this year. It amounts to Berkshire’s biggest stock investment as of the end of March, noted the report. In the first quarter of 2018 alone it purchased 75 million shares of the company with Buffett telling CNBC that Apple is a “unbelievable company.” He went on to say that Apple “earns almost twice as much as the second most profitable company in the United States."

Buffett had long shied away from investing in technology companies, saying he didn’t understand the business models. He does regret not buying shares of Alphabet Inc. (GOOG) and Amazon.com Inc. (AMZN) in their early days. The investor, who still uses a flip phone, said Apple’s products have a hold on users and he sees it more as a consumer company than a tech firm. (See also: Buffett's Berkshire Hathaway Buys 75 Million More Apple Shares.)

Vanguard, BlackRock, State Street Also Benefit

Buffett’s Berkshire isn’t the only one to benefit from Apple surpassing the $1 trillion milestone. Vanguard, BlackRock Inc. (BLK) and State Street are also top Apple shareholders, with Vanguard the largest, holding 342 million shares, noted the Journal, citing FactSet. Combined, the three fund companies have a 16% stake in the iPhone maker, spread across mutual funds and exchange-traded funds.