1
As you know, there might be an upcoming hard fork of BTC to enlarge the block size.
Will the new currency Bitcoin Unlimited be a different currency or will it be compatible with Bitcoin with a fixed exchange rate between the new and the old currency?
2
If the two projects both persist, they would be freely traded one for the other. A fixed price could only be established if someone with unlimited funds guaranteed an exchange rate, which naturally can't happen because there is a limited number of tokens.
If the hardfork occurs you will have whatever Bitcoin you had on both these chain-tips.
Note, that to Bitcoin Unlimited nodes as it's currently implemented the Bitcoin chain would still appear valid, and if the latter ever grows longer after the chain split, BU nodes would reorganize back to the Bitcoin chain. This could of course be prohibited by setting BU nodes to require one of the blocks created after the chain split to be part of their longest chain.
So, as long as it's a hard fork, people can use their BTC in the BU environment, so there is no need to sell BTC and to buy BU, thus BTC won't have a huge value drop in my assumption. Do I think right? – modiX – 2017-03-23T13:31:09.093
2Some large Bitcoin holders have announced that in the event of a fork, they'd sell either one side or the other. I'd be expecting a surge in trade volume and volatility for both BTC and BU. Some exchanges might even be overburdened by the traffic. As block intervals would increase for both chains, fees would spike at the same time at least for BTC (since the split would be initiated by larger blocks establishing a BU chain). I find it hard to predict what would happen, but would expect chaos. – Murch – 2017-03-23T13:38:42.440
Thanks, I missed the point the fork will include the whole history, so copying my BTC to BTU, too. BTC will stay the main imo (one to rule them all). But how dare they call the fork Bitcoin Unlimited, hurting a well hard established strong brand by splitting it? It's a rhetoric question, I just realized there will be a long dry time for BTC. – modiX – 2017-03-23T23:39:46.830
Yes, the brand is Bitcoin's most valuable asset. The network could be moved and the technology is already open source. Another major issue with the common history for both forks is the possibility of replay attacks
– Murch – 2017-03-24T06:20:52.407