Title page This file contains directions for downloading historical data on stock prices. It is intended for use with Project 2, Stock Option Pricing, in Part 1 of Mathematics for Business Decisions. YAHOO SITEYAHOO SITE BUSINESS WEEK SITEBUSINESS WEEK SITE Part 1: Probability & Simulation The M athematical A ssociation of A merica Published and Distributed by © 2003 by The Arizona Board of Regents for The University of Arizona. All rights reserved. Mathematics for Business Decisions materials may be used by individuals for study or examination. Any redistribution is strictly prohibited. Any use for group or organized instruction requires written approval from the authors. Mathematics for Business Decisions Part 1 Release 1.0, 2003 DOWNLOADING HISTORICAL DATA ON STOCK PRICES DOWNLOADING HISTORICAL DATA ON STOCK PRICES Written By Dr. Richard B. Thompson Department of Mathematics University of Arizona Business Projects By Dr. Christopher G. Lamoureux Department of Finance University of Arizona Updated June 21, For distribution only to licensed users of Mathematics for Business Decisions, Part 1, Release 1.0.

1. YAHOO The web site is a good source for historical data on stock prices. We will illustrate the use of this site, as visited on January 11, 2002, with the Walt Disney data for the Class Project. The project calls for 8 years of weekly data, ending on Friday, January 11, The site first requests the stock symbol DIS. Downloading Stock Records, Yahoo (material continues) finance.yahoo.com/q/hp Downloading Stock Records. Yahoo Start  DIS 2. Click on Go1. Enter DIS. Problems with the Yahoo site may occur with Netscape browsers. If this happens, try Internet Explorer. Back to Project 2 Histograms Back to MBD Part 1 Projects Back to MBD Part 1 Business Background

Downloading, Yahoo Start  Downloading Stock Records. Yahoo: page 2  (material continues) 3. Click on Historical Prices. 4. Enter the starting and ending dates. 5. Select Weekly. 6. Click on Get Prices. Yahoo displays weekly closes for Fridays, but labels the weeks with the preceding Monday. The closing price on Friday, January 11, 2002 is listed for “Week of” Monday, January 7, The starting date for our data is automatically moved back to the Monday before January 11, finance.yahoo.com/q/hp Back to Project 2 Histograms Back to MBD Part 1 Projects Back to MBD Part 1 Business Background

Actual close on January 11, 2002 Adjusted close on January 11, 2002 Monday Downloading, Yahoo  Downloading Stock Records. Yahoo: page 3  Start What is the “adjusted close?” Yahoo starts on the date of a site visit, assumes that all cash dividends have been reinvested, and then adjusts actual Friday closes to account for the effect of stock splits and dividends. (material continues) finance.yahoo.com/q/hp Back to Project 2 Histograms Back to MBD Part 1 Projects Back to MBD Part 1 Business Background

Actual close on November 30, 2001 Adjusted close on November 30, 2001 Dividend paid Monday Avg. Vol. Downloading, Yahoo   Start Downloading Stock Records. Yahoo: page 4 (material continues) finance.yahoo.com/q/hp Back to Project 2 Histograms Back to MBD Part 1 Projects Back to MBD Part 1 Business Background

In our example, the actual and adjusted closing prices agree back to the week of Monday, December 3, Walt Disney rose $1.88 from $20.47 on Friday, November 30 to $22.35 on Friday, December 7. However, the $0.21 dividend paid on Wednesday, December 5 during this period, increased the actual gain to $2.09. Subtracting this from $22.35 gives a value of $ This is the adjusted close for Friday, November 30 (the week of Monday, November 26), rounded to whole cents. Continuing these adjustments back to January 14, 1994 (the week of January 10, 1994), Yahoo finds an adjusted close of $ Perhaps “adjusted value” would be a better term than adjusted close. The interpretation is that $14.95 invested in Walt Disney stock on January 14, 1994, would be worth the adjusted closing price on the date of our site visit. Downloading, Yahoo   Start Downloading Stock Records. Yahoo: page 5 (material continues) finance.yahoo.com/q/hp Back to Project 2 Histograms Back to MBD Part 1 Projects Back to MBD Part 1 Business Background

Downloading, Yahoo Since the Yahoo site computes adjusted closing prices backward from the date of the site visit, the adjusted closes may change from one site visit to the next. This will not be a problem for us, since our only interest in historical closing prices involves the ratio of one adjusted weekly close to that of the preceding week. Any slight variation in the adjusted closes will have no significant effect on estimated option values. The displayed closing prices will be the same, no matter when the site is visited. Once the historical data for a stock is displayed, on the screen, you can save the records as an Excel spreadsheet. To do this, scroll down to the end of the records and click on Download Spreadsheet Format. This will export the data in a generic spreadsheet format. Save this exported file in some convenient folder, and then open it in Excel. Once this is done, the data can be edited and saved as an Excel file.  Start Downloading Stock Records. Yahoo: page 6 (material ends) finance.yahoo.com/q/hp Back to Project 2 Histograms Back to MBD Part 1 Projects Back to MBD Part 1 Business Background

Click on Get Report Problems with the Business Week site may occur with Netscape browsers. If this happens, try Internet Explorer. 1. BUSINESS WEEK A web site maintained by Business Week can also be used to obtain historical data on stock prices. We will illustrate the use of this site with our Class Project data for Walt Disney stock. Enter the stock symbol, DIS. Downloading Stock Records, Business Week (material continues) host.businessweek.com/businessweek/Historical_Quotes.html Downloading Stock Records. Business Week Start  Back to Project 2 Histograms Back to MBD Part 1 Projects Back to MBD Part 1 Business Background

Enter the beginning and ending dates of the period for which you want records, and select the desired frequency of the price data. IMPORTANT, in order to get accurate data you must use an ending date that is one week later than January 11, Downloading, Business Week Start  Downloading Stock Records. Business Week: page 2  (material continues) Click on Get Quotes 01/18/02 host.businessweek.com/businessweek/Historical_Quotes.html Back to Project 2 Histograms Back to MBD Part 1 Projects Back to MBD Part 1 Business Background

The historical data is displayed from start to end, with Friday dates. The close on Friday, January 11, 2002 is is the actual closing price on that date. The “close” and all other data for Friday, January 18, 2002 is not correct, and should be ignored. Downloading, Business Week Start  Downloading Stock Records. Business Week: page 3  (material continues) host.businessweek.com/businessweek/Historical_Quotes.html Ignore Entire Row Actual Close Back to Project 2 Histograms Back to MBD Part 1 Projects Back to MBD Part 1 Business Background

To work with the Business Week data, use your internet browser to save the page as an HTML file on some drive in your computer. Open this file in Excel, and use Save As to save the file as a Microsoft Excel Workbook. Delete all unneeded rows and columns in the Excel file. This should include the final row with data for Friday, January 18, Downloading, Business Week Start  Downloading Stock Records. Business Week: page 4  (material continues) host.businessweek.com/businessweek/Historical_Quotes.html Back to Project 2 Histograms Back to MBD Part 1 Projects Back to MBD Part 1 Business Background

Comparing the Business Week data with that from the Yahoo site, we see that Business Week does not adjust for the payment of stock dividends. However, it does adjust values in all columns, including “close,” for stock splits. Due to the lack of adjustment for dividends, weekly ratios from the Business Week site will not be exactly the same those from the Yahoo site. The difference in computed option values from the two historical data sites will be insignificant. It is preferable to use ratios from the Yahoo site, but either set of data will produce acceptable ratios for your team project. Business Week always adjusts closing prices from the time of the site visit. This can cause a problem if the there has been a stock split between the starting date of your option and the date that you download the data. It is safer to use the Yahoo site to obtain the actual closing price of the stock at the start of your option. Downloading, Business Week Start Downloading Stock Records. Business Week: page 5  (material ends) host.businessweek.com/businessweek/Historical_Quotes.html Back to Project 2 Histograms Back to MBD Part 1 Projects Back to MBD Part 1 Business Background

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