Found 6 exchanges where Hedera is traded for BTC. According to the data on 7 August the most optimal price to exchange HBAR for BTC is ₿0.0000011 for 1 Hedera. This rate is fixed at HitBTC at the maximum trading volume of the pair HBAR/BTC - 1 BTC.
The maximum daily trading volume is observed in the HBAR/TRY trading pair at Bitci and reaches ₿ 77.81 (3.05% of the exchange's total trading volumes) at the price ₿ 0.0000011 per 1 HBAR.
The minimum price to buy HBAR for BTC is 0.0000011 - on the exchange Bitcoin.com.
The maximum price to buy HBAR/BTC is 0.0000011 - on the exchange WhiteBIT.