# Ex-Post: Definition, Calculation, vs. Ex-Ante

> **Definition**
>
> “Ex-post” is a term used by actuaries to describe an asset’s historical returns.

## What Is Ex-Post?

Ex-post is a word for what happens after an event, or the outcome of a decision. In the financial industry, it refers to [actual returns](https://www.investopedia.com/terms/a/actualreturn.asp).

The use of [historical returns](https://www.investopedia.com/terms/h/historical-returns.asp) has customarily been the most well-known approach to forecast the probability of incurring a loss on [investment](https://www.investopedia.com/terms/i/investment.asp) on any given day. Ex-post, which is Latin for “after the fact,” is the opposite of [ex-ante](https://www.investopedia.com/terms/e/exante.asp), which means “before the event.”

### Key Takeaways

*   Ex-post, a word for actual returns, refers to things that happen or are analyzed after a certain event has occurred.
*   Ex-post analysis looks at financial results after they have occurred and utilizes them to predict the likelihood of future returns.
*   The ex-post value is obtained by taking into consideration the beginning and ending value of an asset, the growth and decline of the asset, and any earned income.
*   Ex-post stands in contrast to ex-ante, which uses estimates to gauge future performance. Ex-post is standard practice, as it relies on proven results.

![Ex-Post](https://www.investopedia.com/thmb/ZKvH84ebJdbPwyiAhTqm3JGugnk=/1500x0/filters:no_upscale():max_bytes(150000):strip_icc()/final_expost_definition_1117-64c26095b1294da9b57150b1cd1aa8f4.png)

*Ex-post is Latin for “after the fact”. — Sydney Saporito / Investopedia*

## Understanding Ex-Post

Ex-post information is attained by companies to forecast future [earnings](https://www.investopedia.com/terms/e/earnings.asp). Ex-post information is utilized in studies such as [value at risk (VaR)](https://www.investopedia.com/terms/v/var.asp), a probability study that approximates the maximum amount of loss that an investment portfolio may incur on any day. VaR is defined for a specified investment portfolio, probability, and [time horizon](https://www.investopedia.com/terms/t/timehorizon.asp).

Ex-post [yield](https://www.investopedia.com/terms/y/yield.asp) differs from ex-ante yield because it represents actual values, essentially what investors earn rather than estimated values. Investors base their decisions on expected returns vs. actual returns, which is an important aspect of an investment’s [risk analysis](https://www.investopedia.com/terms/r/risk-analysis.asp). Ex-post is the current [market price](https://www.investopedia.com/terms/m/market-price.asp), minus the price that the investor paid. It shows the performance of an asset; however, it excludes projections and probabilities.

## Calculating Ex-Post

Ex-post is calculated using the beginning and ending asset values for a specific period, any growth or decline in the asset value, plus any [earned income](https://www.investopedia.com/terms/e/earnedincome.asp) produced by the asset during the period. Analysts use ex-post data on investment price fluctuations, earnings, and other metrics to predict expected returns. It is measured against the [expected return](https://www.investopedia.com/terms/e/expectedreturn.asp) to confirm the accuracy of [risk assessment](https://www.investopedia.com/terms/r/risk-assessment.asp) methods.

Ex-post is best used for periods less than a year and measures the yield earned for an investment [year to date](https://www.investopedia.com/terms/y/ytd.asp). For example, for a March 31 quarterly report, the actual return measures how much an investor’s [portfolio](https://www.investopedia.com/terms/p/portfolio.asp) has increased in percentage from Jan. 1 to March 31. If the number is 5%, then the portfolio gained 5% since Jan. 1.

## Ex-Post Analysis

Ex-post performance [attribution analysis](https://www.investopedia.com/terms/a/attribution-analysis.asp), or benchmark analysis, gauges the performance of an investment portfolio based on the return of the portfolio and its correlation with numerous factors or benchmarks. Ex-post analysis is the traditional approach of performance analysis for long-only funds.

Ex-post performance analysis typically centers on regression analysis. An analyst executes a regression of the portfolio’s yields vs. the returns of the [market index](https://www.investopedia.com/terms/m/marketindex.asp) to determine how much of a portfolio’s profit and loss might be the result of market exposure. The regression provides the portfolio’s [beta](https://www.investopedia.com/terms/b/beta.asp) to the market index and the amount of [alpha](https://www.investopedia.com/terms/a/alpha.asp) the fund was gaining or losing in relation to the market index.

## Ex-Post Forecasting

The formula for calculating ex-post is (ending value - beginning value) / beginning value. The beginning value is the [market value](https://www.investopedia.com/terms/m/marketvalue.asp) when an asset was purchased. The ending value is the [current market value](https://www.investopedia.com/terms/c/cmv.asp) of an asset.

Ex-post is a forecast prepared at a certain time that uses data available after that time. The forecasts are created when future observations are identified during the [forecasting](https://www.investopedia.com/terms/f/forecasting.asp) period. It is used to observe known data to assess the forecasting model.

## How Is Ex-Post Information Used?

Companies attain ex-post information to forecast future earnings.

## How Does Ex-Post Factor Into Analysis?

Ex-post performance attribution analysis gauges an investment portfolio’s performance based on the portfolio’s return and its correlation with numerous factors or benchmarks. It is also known as benchmark analysis.

## What Is the Formula for Ex-Post?

Subtract beginning value from ending value, and divide the result by beginning value, to determine ex-post.

## The Bottom Line

Ex-post looks at something after it has already happened, allowing for assessment and refinement of strategies and decision-making processes. Ex-post is a word for actual returns, and ex-post analysis views financial results after they have occurred and utilizes them to predict the likelihood of future returns.