If I discovered (and I think I have) that I made an error on my 2000 taxes causing me to pay more than I should’ve, how long before I cannot get it fixed?
And how best to re-do a prior year’s taxes? Can I just go into an H&R Block and ask “could you fix my (potentially) $3000 error from five years ago?”
Basically, back then I sold some stock obtained through an employee stock purchase plan and made a large profit: stock went from $15 per share (the grant price) to over $90 per share (where I sold). And based on information learned this year (I exercised some stock options last fall), I think I paid taxes on that ESPP sale twice.