Jim, for an initial position in BRKB, is now a good time for an at the money covered call or an at the money put?

Well, the first step is to decide whether or not it's a good time to initiate an investment. My conclusion is that it isn't a good time for an initial position, in this case.

The second step is the decision of the best WAY to enter that position. Stocks, futures, options, calling your bookie, a combination of the above, whatever. But if the first step isn't opportune, it's hard to find something suitable in the second step. First "if", then "how".

My current thoughts are more along the lines of "let's sit on cash and wait for some good opportunity". That might be a good plan, it might not, but I'm cool with it.

Of course, writing puts at a strike price that represents a good entry certainly improves your return on your cash pile until you achieve your entry goal. The problem is that a good entry price is so far below the current market price that the returns are pretty low, considering that you've committed yourself to a specific (though wonderful) investment choice before knowing what the next market swoon will actually look like. Maybe Berkshire drops 15% and (say) Alphabet drops 80%...I love Berkshire, but I'd rather keep the flexibility to be an Alphabet buyer on that day. The current low return from low-strike Berkshire puts wouldn't be enough to compensate me for giving up the wonderful flexibility of cash. I did the put writing, profitably as it turns out, when the market price was $430ish and I thought a fair entry was $400ish, but not now with such a large gap.

Jim