Article seems to suggest if you make gains but lost them later you still need to pay tax on the gain?! That's strange..
It happens when you exchange one type of token for another, that's the point being made. Broadly: the gain is calculated any time the value of the property is realised by using it to purchase some other thing. Using the thing to purchase money is one way of realising its value, and makes the calculations easy; but when used to purchase some thing other than money, the transaction can be assigned a monetary value and…
See separate point re losses that happen next year that's tough luck lol. Govt not gonna help. Unless you go fully bust and they have nothing to collect.