I think price rises for BTC creates two different but interesting dynamics with regards to the altcoin market. On the one hand, some people that have been in the alts for a while will sellout their holdings of coins that are moving slowly, cash out BTC. With the cashed out BTC proffits they will wait patiently, buy more BTC on a correction and then invest again in their favorite alts.
There are also ofcourse, those that are completely new to the entire crypto world who see news of BTC price rise and inmediately panic jump into the bandwagon. Once there they realize there are many other coins and a few of them decide to enter into the Alternative Cryptocurrencies. So new money steps into the Alts while some old money leaves from the Alts. How much new money vs how much old money leaves the alts? I have no idea really, it might be inbalanced one way or another.
I've always assumed that if BTC is strong then its purchasing power against other alts is stronger also, hence xxx/BTC goes down. I mean that's only natural in the Forex right? If the the Dollar goes strong relative to the Euro, then EUR/USD goes down.... right?
That seems to correlate in the Bitcoin world, but I'm not sure to what extent alts without a fiat pair are subordinate to BTCs value.
