Ann: Record half year revenue up 82%, page-11

Hard to say - it's not like a large bank, miner or retailer where the underlying value doesn't change much from year to year, and you sell when the value metrics (FCF, P/E, ev/EBITDA) become so stretched that the risk of correction outweighs the capital gains tax hit.

Based on profitability of equivalent businesses at a more mature stage there's a decent chance that FDV becomes worth at least 10x current market value. There's also a decent chance that some sovereign risk type event wipes out most of its value in the near future.

Given those risks, right now I'd take a hard look if the price went into the $2's. And while I'd take another bite if it fell back to around 50c, it wouldn't be a large one.