I read someone claim the last controversial ETF took seven years.  It might be a couple years from now, or it could even occur in 2017.  I could see them fast tracking it if the post-halving charts don't look like a completely ridiculous pump and dump going from like $500 to $10,000 and back to $1000 again.  People would think that's kind of suspicious.  If it went from $500 to $3200 then back to $1600, they would consider that OK and just price discovery/growing market.