Motivation

The attached sample data and request files were constructed to illustrate the use of the EventStudyTools R-package.

The files hold data about the addition of several well known firms to the S&P 500 index in the late 1990s. With this data, the R package will investigate for you the question whether a company’s stock value increases if the firm is added to the S&P 500 index. This is a common research question and has been adressed, among others, by Anthony W. Lynch and Richard R. Mendenha in a 1997 study: They found a positive effect of about 3.8% over the period starting the day after the announcement and ending the day before the effective date of the change.

You can use our R-package to easily investigate such and similar questions.

Perform an Event Study from R

Authentication

For performing an Event Study with our API you need:

API url (defaults to http://api.eventstudytools.com)
API key

You get a free API key from our website EventStudyTools. In the first step we need to authenticate to the web API. There are three ways to handle this two parameters:

apiUrl <- "http://api.eventstudytools.com"
apiKey <- "Please insert your key here"

Option 1 and 2: You can save API key and URL in the options object

# The URL is already set by default
# options(EventStudy.URL = apiUrl)
options(EventStudy.KEY = apiKey)

# use EventStudy estAPIKey function
estAPIKey(apiKey)

# initialize object
estSetup <- EventStudyAPI$new()

Option 2: Set the API Key and URL directly during the EventStudyAPI R6-class initialization

# Setup API Connection
estSetup <- EventStudyAPI$new(apiUrl)
estSetup$authentication(apiKey)

This API package is designed to perform all analyses we provide on our website. Furthermore, all parameters can be set. You are able to set every parameter in R (we will provide more details later), or you can perform a fast Event Study with default parameters.

Event Study with Defaults Parameters

There will be soon a separate vignette for setting parameters.

Event Study Types

Our API offers different types of Event Studies:

Return Event Study: arc
Trading Volume Event Study: avc
Abnormal Volatility Event Study: avyc

Default parameters for all type of above Event Studies are:

Benchmark model: Market Model for arc and avc and GARCH(1, 1) Model for avyc
Statistics: All available test statistics are calculated
Result file type: csv
Return type calculation: log
Handling non-trading days: later

The type of Event Study can be set by parameter:

estType <- "arc"

Data Files

By default all data files must be named as follows. Furthermore, they have to be in the current directory:

01_RequestFile.csv
02_firmData.csv
03_MarketData.csv

You are also able to set custom file names and paths by defining it in a named vector:

dataFiles <- c("request_file" = "01_RequestFile.csv", 
               "firm_data"    = "02_firmData.csv", 
               "market_data"  = "03_MarketData.csv")

Results

All results will be written by default into the directory ./results. You can easily change this path by setting it as a parameter:

resultPath <- "results"

Attention

If the resultPath do not exist, the R package will create this directory.

Performing the Event Study

Finally, the Event Study is performed by:

estResult <- estSetup$performDefaultEventStudy(estType    = estType,
                                               dataFiles  = dataFiles, 
                                               destDir    = resultPath)

It will write all result files into the result directory. Furthermore, results will be parsed into a R object.

Data File Description

For performing an Event Study we need three files (file names can be chosen arbitrarly):

A request file where the structure of the Event Study is defined
A firm data file containing the stock data for each firm defined in the request file
A market data file containing the reference market data (multiple reference markets per study are possible)

All files must be saved without header, semi-colon separated and dates has to be in following format: 30.04.1997. In next section we will descripe the file structure based on the S&P 500 example Event Study more detailed. You always find more information (if necessary) on our website: EventStudyTools.

We added the S&P 500 example Event Study to this package. The three necessary files can be easily generated by following command:

library(EventStudy)
getSP500ExampleFiles()

We named the request and data files in following manner:

01_RequestFile.csv
02_FirmData.csv
03_MarketData.csv

In your analysis, you can name them as you want.

Event Definitions: `01_RequestFile.csv`

This csv file contains the event definitions. It contains 9 columns. The order must be in the following way, as the columns are not named in the csv.

Event ID [Integer]: A unique event identifier
Firm ID [String]: The firm name or stock ID. This ID must match the ID in the firm data
Market ID [String]: The reference market ID. This ID must match the ID in the market data
Event Date [30.04.1997]: Date of the event
Grouping Variable [String]: This column is used to group events. Most test statistics are based on looking at groups.
Start Event Window [Integer]: This integer value defines the start of the event window. This value must smaller or equal zero (e.g. trading days before event).
End Event Window [Integer]: This integer value defines the end of the event window. This value must greater or equal zero (e.g. trading days after event).
End of Estimation Window [Integer]: This negative value defines the end of the estimation window (counted from event day).
Estimation Window Length [Integer]: Length of the estimation window

In the following example, we have an event window of [-2, 2] (an event window of length 5), an estimation window of length 120, and the estimation window ends 11 days before the event.

library(readr)
df <- readr::read_delim("01_RequestFile.csv", col_names = F, delim = ";")
names(df) <- c("Event ID", "Firm ID", "Market ID", "Event Date", "Grouping Variable", "Start Event Window", "End Event Window", "End of Estimation Window", "Estimation Window Length")
knitr::kable(head(df), pad=0)

Event ID	Firm ID	Market ID	Event Date	Grouping Variable	Start Event Window	End Event Window	End of Estimation Window	Estimation Window Length
75510	Adobe Systems	SP500	30.04.1997	Addition	-2	2	-11	120
64390	Progressive	SP500	25.07.1997	Addition	-2	2	-11	120
23473	Cincinnati	SP500	16.12.1997	Addition	-2	2	-11	120
70500	Coca-Cola Enterprises	SP500	01.10.1998	Addition	-2	2	-11	120
70519	Travelers Group	SP500	01.10.1998	Addition	-2	2	-11	120
76149	Safeway	SP500	05.11.1998	Addition	-2	2	-11	120

Attention

The first column (Event IDs) must be unique and numeric.

Firm Data: `02_FirmData.csv`

The stock data for each firm defined in the request file. It contains 3 columns.

Firm ID [String]: The firm or stock ID. This ID must match the ID in the Firm ID in the request file.
Date [30.04.1997]: Date of the closing price.
Closing Price [Double]: Closing price of volume of that day.

The following table shows the first 20 entries of our example firm data.

library(readr)
df <- readr::read_delim("02_FirmData.csv", col_names = F, delim = ";")
names(df) <- c("Firm ID", "Date", "Closing Price")
knitr::kable(head(df))

Firm ID	Date	Closing Price
Cincinnati	01.10.1996	58.000
Cincinnati	02.10.1996	57.000
Cincinnati	03.10.1996	56.750
Cincinnati	04.10.1996	57.500
Cincinnati	07.10.1996	57.625
Cincinnati	08.10.1996	57.750

Firm Data: `03_MarketData.csv`

This file is similary structured as 02_FirmData.csv:

Market ID [String]: The market ID or stock ID. This ID must match the ID in the Market ID in the request file.
Date [30.04.1997]: Date of the closing price.
Closing Price [Double]: Closing price of volume of that day.

The following table shows the first 20 entries of our example firm data.

library(readr)
df <- readr::read_delim("03_MarketData.csv", col_names = F, delim = ";")
names(df) <- c("Market ID", "Date", "Closing Price")
knitr::kable(head(df))

Market ID	Date	Closing Price
SP500	30.09.1996	100.0000
SP500	01.10.1996	100.2575
SP500	02.10.1996	100.9747
SP500	03.10.1996	100.7958
SP500	04.10.1996	102.0587
SP500	07.10.1996	102.3380

You are also able to apply a Fama-French 3-Factor Model or a Fama-French Momentum-4-Factor Model. This will change the neccessary data you need for performing an Event Study (e.g. by adding Fama-French Factors). You find more information at https://www.eventstudytools.com/instructions-axc.

More Vignettes

Event Study: Parameters: In this Vignette we show how you can set parameters and which parameters are allowed.
Graphics: In this Vignette we show you how to generate nice (static or interactive) graphs (coming soon)
Data Preparation: In this Vignette we show you how to get and prepare data for your Event Study from R (coming soon)
RStudio Addins: We wrote a RStudio addin for performing different types of Event Studies
- Abnormal Return Event Study
- Abnormal Volume Event Study
- Abnormal Volatility Event Study

How to Cite

Please cite our work in your publication.

Introductionary Use Case: Firm Addition to S&P500

Dr. Markus Schimmer and Dr. Simon Müller

2021-12-19

Motivation

Perform an Event Study from R

Authentication

Event Study with Defaults Parameters

Event Study Types

Data Files

Results

Performing the Event Study

Data File Description

Event Definitions: `01_RequestFile.csv`

Firm Data: `02_FirmData.csv`

Firm Data: `03_MarketData.csv`

More Vignettes

How to Cite

Introductionary Use Case: Firm Addition to S&P500

Dr. Markus Schimmer and Dr. Simon Müller

2021-12-19

Motivation

Perform an Event Study from R

Authentication

Event Study with Defaults Parameters

Event Study Types

Data Files

Results

Performing the Event Study

Data File Description

Event Definitions: 01_RequestFile.csv

Firm Data: 02_FirmData.csv

Firm Data: 03_MarketData.csv

More Vignettes

How to Cite

Event Definitions: `01_RequestFile.csv`

Firm Data: `02_FirmData.csv`

Firm Data: `03_MarketData.csv`