In CNBC's latest issue of Fast Money, Brian Kelly, CEO of BKCM, an encryption investment company, reiterated his view that traders should track the number of active Bitcoin addresses as a leading indicator of Bitcoin's next price action. . Kelly said that due to the recent decline in active addresses, he believes that bitcoin prices will fall in the near future. And added that if this happens, then the callback will be a once-in-a-lifetime opportunity. Kelly also outlined some of the signs he was looking for. He believes that these signs indicate that BTC is about to usher in a new round of ups; as for the decline in Bitcoin's active address, Kelly said institutional traders may increasingly turn to derivatives. For example, the Bitcoin futures of the Chicago Mercantile Exchange (CME).