I give Mark and Priscilla a lot of credit for this. There's a big difference between 50% and 99%. There's a big difference between leaving your children a few hundred million and many billions. They have certainly exemplified the challenge to ''put your money where your mouth is''.

Having said that, the first thing I thought of was the tax implications. If the shares were to eventually be sold (but not donated), the State of California alone would earn roughly 6 billion dollars in tax revenue. And the Federal Government another 13 - 15 billion. Assuming a lot of variables that could push the value up or down, of course, and the fact that they would be unlikely to sell the majority of their shares any time soon. My understanding is that by donating the appreciated stock to a charity, under current laws, there is zero tax due. I wonder if there's a state financial forecaster or analyst in Sacramento having a bad day today.