If you can't beat 'em, join 'em.

It's not surprising that mimicking Warren Buffett's moves over the years would leave you well ahead of the pack. That's why it's great news that as an elephant-sized investment vehicle, Buffett's Berkshire Hathaway (NYSE:BRK-A) is required to periodically report some of its investments.

What's he been up to lately? Berkshire's latest quarterly filing shows substantial purchases in two of his favorite banks: Wells Fargo (NYSE:WFC) and US Bancorp (NYSE:USB). Berkshire purchased 12 million and 1.5 million shares, respectively, in the banks during the quarter ended March 31.

How surprising is this? Not very. At this year's Berkshire annual shareholder meeting, Buffett went as far as saying Wells Fargo would be the company he’d put his entire net worth in (if forced to pick one company) when it traded in single digits earlier this year. Wells Fargo, he noted, "will be a lot better off in a couple of years than if none of this had happened," referring to the competitive advantages gained when competition implodes. He also went as far as saying he "would love to buy" either bank in its entirety -- a goal hampered by regulations that would force Berkshire to become a bank holding company, which could greatly disadvantage the flexibility of its business model.

Berkshire also purchased about 4 million shares of Johnson & Johnson (NYSE:JNJ) during the quarter, just months after selling a substantial amount. Why the about-face? Day trading? Market timing? Diminished cognizance that comes with old age? Nah. Buffett recently noted that last year's J&J sales were simply a factor of wanting more cash after plowing several billion into Goldman Sachs (NYSE:GS) and General Electric (NYSE:GE).

On the sell side, the most notable was a substantial reduction of ConocoPhillips (NYSE:COP) stock. In this year's annual shareholder letter, Buffett said of his ill-timed Conoco bet:

I bought a large amount of ConocoPhillips stock when oil and gas prices were near their peak. I in no way anticipated the dramatic fall in energy prices that occurred in the last half of the year. I still believe the odds are good that oil sells far higher in the future than the current $40-$50 price. But so far I have been dead wrong. Even if prices should rise, moreover, the terrible timing of my purchase has cost Berkshire several billion dollars.

But the stock sales don't necessarily mean he's giving up for good. In a company statement, Berkshire disclosed that it's selling shares to gain tax advantages -- likely booking losses to offset capital gains on other investments. What will be interesting is whether Buffett jumps back into the oil giant over the next few months.

Still intrigued? We've got more Buffett coverage than you can shake a stick at:

Fool contributor Morgan Housel owns shares in Berkshire Hathaway. Berkshire Hathaway is a Motley Fool Stock Advisor and Motley Fool Inside Value selection. Johnson & Johnson is a Motley Fool Income Investor recommendation. The Fool owns shares of Berkshire Hathaway, and has a disclosure policy.