Following the stock and bond, and other markets for some years now, I saw that they are all rigged. I would be surprised if the value of altcoins are not. Just look at graphics and you will see this. Altcoins market has became a field for speculations, and maybe only the big players can tell something, but they won't. This is on the short term. On the long term, an year or less, I think that the value of important altcoins will grow, more if the world economy will feel bad, or unstable. For example, the grows of Bitcoin in this winter was done because chinese had a bad feeling about reminbi's value, and the huge debt of banks in China.

On the other side, if the international tension will rise, I think will not be a good thing for altcoins.