It's safe to say that even the most conscientious investors rarely look forward to new regulatory filings with the Securities and Exchange Commission. But the quarterly updates on Warren Buffett's investment vehicle, Berkshire Hathaway (BRK.A -0.76%) (BRK.B -0.69%), are quite the exception.

Every three months, institutional money managers like Buffett have to file Form 13F, listing updates on the contents of their equity portfolios. Berkshire Hathaway's are eagerly digested by Buffettologists everywhere. While Berkshire's latest 13F, released on Monday, didn't reveal as many significant changes as others in recent years, it did indicate a new sector of interest for the fabled investor and his team. Read on to find out what kind of companies have become a big draw for Warren lately.

Safe as ...

The latest 13F, covering the second quarter, revealed that Berkshire opened three new positions, all of which are in the same sector -- homebuilding. The trio consists of D.R. Horton (DHI 0.78%), Lennar (LEN 0.98%), and NVR (NVR -1.01%).

D.R. Horton was far and away the largest of the three buys, with Berkshire snapping up nearly 6 million shares worth some $726 million. The count goes rapidly down from there, as the tally for NVR is 11,112 (worth more than $70 million) and that for Lennar is 152,572 (worth about $17 million).

The 13F is purely an informational document, a snapshot of the holdings in the portfolio. It doesn't come with any notes, and it entirely lacks commentary. On top of that, Buffett and his Berkshire lieutenants like to keep mum about their investments until they've at least marinated in the portfolio for a while. That is, if the veteran investor ever feels like discussing them at all.

So we don't know the exact reason or reasons for the apparently sudden interest in homebuilding stocks. It's certainly a sector with potential, though, and Berkshire has definitively planted a stake in it.

For the entirety of 2022, D.R. Horton was the No. 1 builder in the U.S. in terms of revenue, according to researcher Statista. Lennar was a close No. 2, while NVR was No. 4. Any investor aiming to buy in at the top of the domestic housing sector would be well served by amassing shares of those three companies.

Sales of new homes popped during the pandemic, which is understandable given the shutdowns and lockdowns engendered by the spread of the coronavirus. After all, people wanted the best housing situation possible since they were going to be spending so much time in their domicile. As the worst of the pandemic began to fade, so too did sales.

However, that was then and this is now. New home sales have been ticking up in recent months from late 2022 levels, although they're still consistently down on a year-over-year basis. This, despite interest rates that are dramatically higher than those inside the pandemic. Supply remains constrained, and demand obviously continues to be hot. This provides a very good foundation for a trusted homebuilder's growth.

Build it and he will come

Berkshire's purchase of the D.R. Horton, Lennar, and NVR package was arguably the most surprising and significant move during the quarter. Berkshire did its usual liquidating of, and adding/subtracting to, various positions in the equity portfolio. None of those moves marked an overly dramatic change, however.

So these anchor stakes in housing stocks are surely worth watching. Will Berkshire stick with the sector if interest rates remain lofty, or if demand for new builds eases once again? Buffett usually stays with his bigger investment ideas for the long term; we'll see how long he keeps his eye on this particular ball.