Quick question on rebalancing a portfolio. Let's say that 10% of my portfolio is in something really speculative such as bitcoin (speculative for me at least)...now I've said to myself that I'm only prepared to have 10% of the value of my portfolio in this investment in case it goes bust.
As an example, let's say my 10% is made up of 10 bitcoins worth +- 4000 USD. The bitcoin price goes up by 30% taking my speculative investment to 5200 USD.
Generally speaking, when rebalancing portfolios, what should be done here? Should I sell off the 1080 USD as profit, to take my speculative investment back to 10% of my current portfolio value?