Historical Volatility

Идея простыми словами

Volatility measures risk: the bigger and more frequent the moves, the higher it is. Expressed per year, it can be compared with option prices and other markets.

Как считается

Take the logarithmic return of each candle, compute their standard deviation over N candles and scale it to a year (√252 for daily candles, adjusted for other timeframes), in per cent.

r = ln(close ÷ close₋₁)
HV = stdev(r, N) × √(periods per year) × 100

Как использовать

• Position sizing: smaller positions when volatility is high.
• Spotting quiet periods that often come before big moves.

Выводы

• Compare with the ticker's own history: 10% is high for EURUSD and low for bitcoin.

На что обратить внимание

• Backward-looking: it measures what has been, not what will be.

Немного истории

Standard deviation of returns became the textbook risk measure with modern portfolio theory (1950s) and option pricing (1970s).