Odaily Planet Daily News: The EthVol (Bitcoin Volatility) Index, launched by financial index company T3 Index and options trading platform LedgerX, fell to 55.59 yesterday, a daily decline of 2.18%, close to the lowest level since the end of February. The EthVol Index measures the 30-day expected implied volatility derived from the price of tradable Bitcoin options. Implied volatility refers to the volatility implied by the actual option price. It is the volatility inferred by substituting the actual option price and other parameters except volatility σ into the B-S option pricing formula.