Subject: Re: Apple today
It’s so odd to me that Berkshire’s stock price often falls while Apple stock is getting bid up.
Any logical reason you can think of for this?

Personally I think the simplest explanation is that on any given day (or week or month) in the markets, things lean either conservative/safe or speculative/growth.
Apple is considered to be speculative/growth, but Berkshire is considered to be conservative/safe, so they advance at different times at short time scales.

As others noted, I wouldn't exactly call it entirely "logical".

Jim