From general observations, I see three reasons to split a stock: 1. Lower the stock price. 2. Raise more money. 3. Offset bad news.
Last year the stock split and rushed right back up to a high price and a very high PE ratio. Why split it again? Does Microsoft need more cash? The stock price seemed to be in a holding pattern for the last six months, but seems to be moving back up. If the stock starts falling for some reason, MSFT just needs to announce a split and drive the stock price back up.
Just before the last slipt I heard rumors that the split was impending were being circulated. I wish I listed to them as I sold off some stock just before the split. I thought the sell off of Oct 1997 would occur in 1996.