Since November last year, CME Group and UK-based bitcoin futures exchange Crypto Facilities Ltd have calculated and published the BRR, which consolidates the trade flow of major bitcoin spot exchanges during a calculation window into the U.S. dollar price of one bitcoin as of 4:00 p.m. London time.

Crypto-currency exchanges Bitstamp, GDAX, itBit and Kraken currently contribute prices for calculating the BRR.

Bitcoin is a very small market compared to most. Is there a way to prevent someone from manipulating this rate by buying/selling at specific times? If it's possible, someone will try.