Have you ever wondered how much you gained or lost by making your move at a certain time? Like, how much would the bitcoins sold 10 years ago be worth today?
This is called Opportunity Cost and the lower it is, the better your timing decision was. Of course, no transactions happen in the vacuum - by selling one asset you could buy another one, and this is already included in your Returns. But the Opportunity Cost may give you this little bit of perspective.
You can add it on the Portfolio's Transactions table, along with Current Market Value.
In addition, there's a built-in support for Revolut Investments and Spanish Savings Income taxes.