I thought about some theories last night. Some pretty idiotic, but you have to be creative:

1. Tech people/AI people (e. g. Apple) are finally discovering that tech could be overpriced and shifting to safe heaven (Berkshire).
2. Cryptocurrency people finally acknowledge that Munger was right (... is worthless) and shifting to safe heaven (Berkshire). 🙂
3. The selling pressure of the Bill and Melinda Gates Foundation has stopped, because they are getting no Berkshire stocks anymore.
4. Buffett wants to do something big and it is easier to do something big in an overpriced world with an overpriced Berkshire stock (like General Re in 1998).
5. There is a big acquisition going on.
If there is a big acquisition, he could be repurchasing shares. That could be the reason why he stopped buying Occidental shares at lower prices.
Thomas Gayner (Markel) in a recent interview: "About Berkshire’s eventual sale of the 3.5% position in his company, Gayner added cryptically, “There are other things going on that I’m not at liberty to talk about.” Your guess is as good as mine on that one.
kingswell.io - Markel CEO tom gayner talks berkshire
6. The P/B valuation method gets less and less relevant.
7. Buffett wants highest flexibility for him and his successor. He doesn´t want Greg to do all the hard capital allocation decisions (+ tax reasons).
Cash has the highest flexibility and has a good risk-free yield.
8. Statistically we are closer to the next recession and in a recession Cash is king.

Any comments?