From: dkb1
Sent: October 14, 2016
Subject: File Number SR-BatsBZX-2016-30

Securities and Exchange Commission:

I previously submitted comment regarding File Number SR-BatsBZX-2016-30 and have the following addendum in support of my request that the Commission delay approval.

1. The consensus of bitcoin miners that controls bitcoin is not just one-man-one-vote. The "vote" is proportional to the miner's computing power(sometimes referred to as "hash"). Currently the country with the most "hash" is China. This trend will likely continue. This represents a severe security issue for bitcoin. Not too long ago private gold ownership was made illegal in the US. It would not be inconceivable for China to do the same with bitcoin if it found a reason or if this tactic became part of a cyber warfare scenario. There is nothing the US could do if China ordered all bitcoin miners to cease and desist. The effect on bitcoin would likely be disastrous. I believe certain levels of encryption may still be viewed as a "weapon" and are denied export. Do we wish to export the control of an entire crypto-currency to a foreign country? With approved ETF in the US, bitcoin might become a much larger part of the world economy at risk.

Thank you.

Dana K. Barish