FUD is the reason it might not get approved.  Gotta love the nanny-state Luddite, authoritarians in charge.

If $300 million comes in during the first week, the impact would be immense.

$300,000,000 at $1000/bitcoin (to make the numbers easy) means 300,000 (more than that at $800-850) bitcoins would be required.  New coins are mined at ~1800/day so that is 166 2/3 days (about 5.5 months!) of new supply.

So, to purchase that much would surely impact the market in a huge way. Now they may be selling some of their own coins to it, so that would decrease the amount that would need to be purchased, but any way you look at it, if approved AND if people invest in it at the rates they project, the price effect would be large.  

And once it starts, momentum players could follow.  The smart ones will realize that the earlier you get in the more upside there is.