For those who hold a stock, the fun begins when a company announces a buy-back because
- the stock price jumps in anticipation (making it take more money and time to buy back a lot of shares, but longs already benefit)
- the stock price doesn't move very much (making it possible for the company to buy-back a lot, which eventually boosts the proce)
- (most likely), a combination of those two things.

I'm not going to get involved in the speculation about how high the price could go, rather I'm just trying to outline the process for newbies.
Erie