Warren Buffett's Berkshire Hathaway more than quadrupled its Chevron stake last quarter. The energy company's stock price also rose 39% last quarter, helping to boost the value of Berkshire's position from $4.5 billion to almost $26 billion.The famed investor's conglomerate also disclosed new positions in Citigroup and Paramount Global, worth $2.9 billion and $2.6 billion respectively as of March 31.On the other hand, Berkshire virtually eliminated its Verizon stake, which was valued at north of $8 billion three months earlier.Burry's Scion Asset Management, which sold most of its US stocks last year, piled back into the market in the first quarter.The hedge fund added the likes of Alphabet, Meta Platforms, and Discovery to its holdings, helping to boost its US stock portfolio's value (excluding options) by 122% to $165 million.Burry and his team also disclosed bearish put options against 206,000 Apple shares. The iPhone maker's stock has tumbled 23% this year as investors — facing the prospect of higher interest rate, stubborn inflation, and a possible recession — have dumped technology stocks.Ray Dalio's Bridgewater Associates disposed of its Tesla stock, and built new stakes in GameStop and AMC Entertainment, in the first quarter of this year.Bridgewater exited Elon Musk's electric-vehicle company after holding about $27 million of its stock at the end of December. In contrast, it bought GameStop shares worth $689,000 as of March 31; it last reported owning the meme stock at the end of 2018.Moreover, Dalio's fund disclosed AMC as a holding for the first time. It owned $667,000 of the cinema-chain's stock at the end of March.Renaissance Technologies doubled down on Tesla, ramped up its GameStop wager, and slashed its AMC Entertainment stake in the first quarter.RenTech, founded by a Cold War codebreaker and former MIT math professor named Jim Simons, boosted its Tesla stake by 109% to 1.6 million shares — worth $1.7 billion at the end of March.Simons' quantitative hedge fund also grew its GameStop position 118-fold to 307,000 shares, valued at $51 million as of March 31.Moreover, RenTech cut its AMC holdings by 61%, and the cinema-chain's stock price slid 9% in the period. As a result, the position's value tumbled by almost two-thirds to $45 million.Stanley Druckenmiller placed a bet against the S&P 500 index, and snapped up a bunch of energy and mining stocks, in the first quarter.Druckenmiller's Duquesne Family Office held puts against 239,600 shares of the SPDR S&P 500 ETF, which tracks the benchmark index, as of March 31.The billionaire investor and his team also boosted their Chevron stake, and added Teck Resources, Coterra Energy, and several other commodity stocks to their portfolio.