[eru]

There can only be predictable news-that-pushes-the-shareprice-lower, if all the people who trade the stock are idiots.

You just need eg a few short-sellers who anticipate those predictable news. They can make a killing by selling the stock at the higher price now and buying it back at the lower price later.

If enough people take this opportunity to make easy money, that brings the share price down today as if the news had already dropped.

So, how do you want to 'artificially' inflate the stock price? Especially how do you want to do it in a way that doesn't require everyone in the market to be idiots only?

[andrewflnr]

If this story was true, we would never see large swings in stock price, because they would already be priced in. But we do. Stock price is simply not an accurate enough predictor to create the incentives we want.

(The most obvious reason this is nonsense is that sometimes the future fall is only predictable to people inside the company. Short sellers don't help here. We need another incentive for those people to do the right thing.)