I have made some capital gains and losses in Bitcoin. As an amateur, I thought I could use cost-averaging as the accounting method.
Investopedia says that I should use FIFO, LIFO or specific lots.
So I've been filing taxes since 2014 using the wrong accounting method. I am actually happy to change to FIFO because it would save me several thousand dollars.
Am I correct in assuming that I need to refile all my taxes for 2014, 2015, and 2016?
If so, what form(s) do I need to do this?
I think this affects my federal, state (PA), and city returns. Philadelphia has a School Income Tax for short term capital gains earned in less than six months. The impact on city and state taxes is relatively small (probably $100 - $200).
I slightly enjoy knowing enough to fill out my own returns - so I would appreciate any assistance that you might provide.