Volatility Decay / 波动率损耗

Volatility decay is the leveraged-product loss mechanism emphasized in vol.121.从昙花一现的分级基金到风头正劲的杠杆ETF：永远不要低估人性的疯狂. In products with [[DailyLeverageReset|daily leverage reset]], alternating gains and losses can reduce the fund even if the underlying asset has not moved much over the full holding period.

The episode uses a simple example: if an index rises 10% one day and falls 10% the next, the index is nearly flat, but a three-times daily leveraged product loses more because the second day’s decline is applied after a leveraged first-day gain. This path-dependence turns volatility itself into a cost.

vol.124.信息过载后如何保持冷静？ | 投资账复盘 adds an April 2025 market-stress reminder. [[DavidWeng|大卫翁]] points to TQQQ and NVDL drawdowns during violent technology-stock volatility to show that realized leveraged-product losses can exceed a naive multiple of the underlying move.

Key Claims

• Volatility decay is strongest when leverage is high and the underlying asset is volatile.
• The mechanism can hurt returns even when the investor’s broad directional thesis is not completely wrong.
• Single-stock leveraged ETFs can suffer larger volatility decay because individual stocks can swing more than broad indexes.
• Product documents can show scenarios where an underlying index rises modestly while the leveraged fund still loses money.
• Vol.124 adds that volatility decay is not only theoretical; it becomes visible exactly when anxious investors are most tempted to use leverage for a rebound trade.

Connections

• Daily Leverage Reset and Leveraged ETF / 杠杆 ETF - structural source of the decay.
• TQQQ, TMF, and NVDL - product examples used by the episode.
• Single-Stock Leveraged ETF / 个股杠杆 ETF - high-volatility version of the mechanism.
• Leveraged Product Suitability and Investment Risk Management - practical investor response.
• Portfolio Suitability and Sleep-Well Portfolio Test / 睡眠理论 - vol.124’s broader fit and behavior response.