I can't seem to wrap my head around this. Let's say we have these fake trades between two currencies
C1 C2 Rate dPIP Trade Value C1 Value C2
Day 1 1 0 10 0 buy 1 10
Day 2 0 10 10 0 sell 1 10
Day 3 10 0 1 -9 buy 10 10
Day 4 0 1000 100 99 sell 10 1000
Day 5 5 0 200 100 buy 5 1000
Day 2 you decide to short and overnight it crashes to 1 on Day 3. So you buy. Your holdings for Currency 1 (C1) go up 10x. But the value of your holdings doesn't change. Likewise you decide to short on Day 4 after seeing a 100x jump. On Day 5 you get cold feet and decide you sold too soon and buy in again at 2x at a loss.
How would you compute the running profits and losses (and which currency should be referenced)? For Example on Day 3 you made 9 of C1. Day 4: 990 of C2, Day 5: you lost 5 of C1. What is the right way to track the P&L because they are relative to each other.
And what is the overall yield? In the end of it all you went from C1=1 to C1=5 or in terms of C2...C2=10 to C2=1000.
EDIT: I've looked that this some more. If I look the change in C2 values during sales and the change in C1 values during buys I think I get the trade-trade yield. Does this look correct? Could then be summed to show the accumulative yield?
Example C1 yield (2nd buy) Yield=((10-1)/1)*100 = 900%
C1 C2 Rate dPIP Trade Value C1 Value C2 Yield %
Day 1 1 0 10 0 buy 1 10
Day 2 0 10 10 0 sell 1 10 0
Day 3 10 0 1 -9 buy 10 10 900
Day 4 0 1000 100 99 sell 10 1000 9900
Day 5 5 0 200 100 buy 5 1000 -50
So if you add up the yields you get 900+9900-50=10750%, but if you look at the yield on C1 it is 500% vs C2 at 1000%. Obviously I'm not doing something right.