Nicola Duke thinks that if the $4400 level is taken out next stop is $7000. I agree. If you take a look at bitcoin's previous ATH it was halfway between a 4.236 and 6.854 Fibonacci extension of the ATH that preceded it. If you look at the Fibonacci extensions in play now $4400 is important resistance and if taken out $7000 is certainly possible. I have
never seen a 6.854 extension in bitcoin take note though. masterluc has mentioned even higher targets that you can see in this Fibonacci extension chart:

These higher targets are low probability though. There is a distinct possibility that the current bitcoin rally can run out of steam between $4400 and $7000 and we would then enter a multi-year bear market. You really want to be mostly out of bitcoin before the next bear market which will be painful. Start taking some profits now. However, there is also a rule to live by:
never sell all your bitcoin.