The marked cap for BTC have increased from 60 to nearly 120b$ since september. In the meantime, the total market cap (BTC excluded) is somehow stable, only 10b$ have gone out of altcoins in the same period.
Where do you think the money that goes into BTC comes from? Margin trading? New money?
Do you know something by fact and a link that can support it
The only explanation I can give to it is the addition of both new money and money spread into other alt coins that have been responsible because another thing that could increase market cap will be the increase in volume which is something that cannot be explained right now, considering the difficulty in mining bitcoin.
But we should not also forget the amount of money that have been pumped into bitcoin as a result of the forks that have happened in recent time which for me its enough to change the way price goes. With a lot of people dumping the forked version, then channeled back into bitcoin is something explaining what we are seeing now.