My Da, a wise man with a terrible sense of humour (sorry Da, but it's true), always told me that "money makes money". He also used to say that one day the Jade Monkey of Zandar would be his and he would use it to rule the world, but that story is for another time.

So Bill Gates is worth, on last count, about $1,432 squizzillion dollars. Yet he has realised there is a limit to the amount of wealth any one family needs. He decided to setup the world's biggest charity, modestly named after himself. This is something I have talked about before and this week's Economist looks at the issue of philanthropy too.

Then you read something like this. I don't quite understand why Bill's charity has decided to invest in equities instead of giving its money away. But this little Chinese company's shares jumped 50% just on the news Gates invested. Nothing else has changed at all. Just they have a new shareholder and it's Bill's charity.

What I want to know is why Gates doesn't employ this tactic more often? If he can make share prices jump like this imagine how much greater the endowment at his charity could be if he just took the trouble to invest a little instead of giving it way.