Share price movements are kind-of-sort-of-rational but not always intuitive. For example, when Apple has a big keynote and announces some significant product, everyone expresses surprise that the share price goes down straight afterwards. Even many smart people get this wrong (“It isn’t based on logic and reason” – The Talk Show episode 53). I hope to explain why the price dropping actually does make sense in this post.

In doing so I’ll likely make some errors. Some of those will be deliberate simplifications. In other cases I’ll probably just be wrong. But either way, I think the gist, if not the details, should give you a good idea of what’s going on.