When a HARDFORK a new string which will have the same historical since that time is born, this means that if you make the fork on a point A, then the entire history of the Bitcoin of the new fork is the same at that point.
This means that if you had 100 bitcoin at the time of the hardfork you will have 100 units of another currency. The value will be different.
Then you will be free to sell it new currency when you create convenient.
Recommendations
-Find information about your provider : look for information on the company that is offering you the service of House of change or portfolio, as you have it on a website or your device. It is important to know if will have support for the new currency.
-Get out your coins from exchanges : all transactions and withdrawals in exchanges will be suspended temporarily in case of hardfork , so, if you want to be able to use your bitcoin during that time, you must withdraw your funds to a personal portfolio before happen.
-Buy or sell: when there is a division in the chain of blocks this will affect the price of Bitcoin, which will now be split in two, and each will have its own behavior in the market.
