So Warren Buffett officially stepped back from running Berkshire Hathaway at the end of 2025, and now Greg Abel is managing what's essentially one of the most closely watched investment portfolios on the planet. We're talking about a $318 billion portfolio that just became Abel's responsibility. The 13F filing from Q4 2025 just dropped, and it tells an interesting story about how concentrated this whole thing really is.

Here's what caught my attention: just five stocks make up nearly 61% of the entire portfolio. Apple sits at the top with 19.5%, followed by American Express at 15.3%, Coca-Cola at 10.1%, Bank of America at 8.2%, and Chevron rounding out the top five at 7.6%. That's a pretty concentrated bet for a portfolio this size, which raises some questions about what Abel might do going forward.

The thing is, Buffett made it pretty clear in his 2023 shareholder letter that certain holdings were meant to be permanent. Coca-Cola and American Express fall into that category, and for good reason. Coca-Cola has been in the portfolio since 1988, Amex since 1991. Both are throwing off absolutely ridiculous yields on cost - we're talking 63% annual yield for Coca-Cola and 39% for American Express based on their original cost bases. When you're getting returns like that, there's basically no financial logic to selling.

But here's where it gets interesting. Abel clearly values getting a good deal, just like his predecessor did. Apple and Bank of America though? They don't look like bargains anymore. Apple's trading at a P/E ratio around 34 these days, which is nearly triple what it was when Buffett first bought shares back in early 2016. Bank of America is another story - Berkshire picked up preferred shares in August 2011 when the common stock was trading at a 62% discount to book value. Now it's trading at a 31% premium to book value. So don't be shocked if Abel starts trimming those positions. Warren Buffett's portfolio might look a little different under new management on those two fronts.

Chevron's position is interesting though. Abel actually used to run MidAmerican Energy, which is now Berkshire Hathaway Energy, so he knows the energy sector inside and out. Chevron's got that integrated model with pipelines, chemical plants, and refineries that hedge against oil price volatility. That could actually get the Coca-Cola and Amex treatment - meaning it sticks around as a core holding.

The broader point here is that while Abel will bring his own style to managing Warren Buffett's portfolio, the fundamental principles aren't changing. Value still matters. Long-term thinking still matters. The difference is you're going to see some portfolio adjustments as Abel puts his own stamp on things, particularly with positions that don't meet his value criteria anymore.