Tools

Signal Decay Calculator

Enter the IC of your alpha signal at multiple forward-return horizons. The tool fits an exponential decay model and estimates the signal half-life and optimal rebalancing frequency.

How it works: The tool takes the natural log of each IC observation and fits a line — ln(IC) = ln(IC₀) − λh — using ordinary least squares. From the slope λ it derives the half-life t½ = ln(2)/λ and a rebalancing guideline based on the point where IC falls below 75% of its peak. Only positive IC rows are used in the regression.

Open source — view or fork the calculator on GitHub (MIT, single dependency-free HTML file). Related tools: Information Coefficient Calculator · Backtest Overfitting Simulator · Cointegration & Pairs Trading Simulator · Signal Combination Simulator · Correlation Heatmap · VPIN & the Volume Clock · Signal Skill Explorer.

Signal IC at Multiple Horizons

Enter the Information Coefficient (IC) of your signal at each forward-return horizon. Only positive IC values are used in the fit.

HorizonIC value
1d
5d
21d
63d

Frequently asked

What is a signal's half-life?
The horizon over which its predictive power (IC) falls to half of its peak. The tool fits a log-linear model to your IC observations by least squares and reports the half-life as ln(2) divided by the decay rate. A short half-life means the edge is gone quickly and must be traded fast; a long one tolerates slower rebalancing.
What do I enter?
Your signal's IC measured at several forward-return horizons — for example 1, 5, 10 and 21 days. Enter your own measured ICs to get your signal's half-life; only positive-IC rows are used in the fit.
How does it choose a rebalancing frequency?
From the point where the fitted IC drops below about 75% of its peak. Trade more often than that and you mostly pay extra transaction costs for IC you have already captured; trade less often and you let alpha decay before acting.
Doesn't transaction cost matter too?
Yes. The half-life tells you how fast alpha fades, but the optimal rebalance also depends on your costs: a fast-decaying signal can still be untradeable if costs exceed the alpha captured per turn. Pair this with the Information Ratio and transaction-cost analysis.
Is this investment advice?
No. It is an educational estimation tool. The results depend entirely on the ICs you supply and assume a simple exponential decay.