When thinking about purchasing large BRK estates through a donation to charity followed by an immediate sale to Berkshire, I think the key is that all sides understand they're getting a fair value for the shares. And who better than Buffett can ensure that this will happen? His integrity is unquestioned.

As Jim points out, buying shares at fair value does nothing directly for BRK shareholders. But it can have significant long term impacts.

It keeps these shares out of the hands of people wishing to gain voting control of BRK. And it strengthens the voting control of BRK family members and loyal shareholders. That seems important to me.

And transferring cash to BRK shares seems likely to yield a higher return long time. But isn't that built into a fair value? Yes but probably discounted in the valuation. I'd take that bet on upside. Here the key would be to be sure that enough ready cash is retained to take advantage of anticipated (or hoped for) elephants. I doubt there will be enough of these estate transfer deals to make this a risk. Particularly where cash now stands on an absolute basis.

Wouldn't charities also want to take that bet? I strongly suspect most of them prefer cash in hand. Donations to already rich institutions such as Harvard or the University of Texas-Austin might prefer to hold the shares. But not churches, hospitals, those providing needed immediate charitable care, etc.

Others on this board can probably think this concept through better than I'm doing. But, in any case, the key is that the shares be transferred at a fair value that all parties can agree to. Who will challenge Buffett's judgment?

Another factor that will be hard to replace with succession. Let's take advantage of it while it is still around.