(Updated May 4, 2020 -- 3AM.)  Questions or comments to: info@hpalumni.org  

This topic is discussed on the very active Tandem Alumni Forum  (operated by former Tandem employees, not by the HP or the HP Alumni Association.)

There are four dates associated with any stock event. The announcement date. The Record Date, specified in the announcement, the date used to determine the number of shares or amount of cash each shareholder receives. The next stock market business day is the Effective Date. The Distribution Date, usually weeks later, is the actual distribution of the additional shares or cash. This table is sorted by Effective Date.

Compare the date when you first acquired Tandem stock with the dates in Column 1. If you later acquired Compaq shares while a Compaq employee, those batches of stock should be tracked separately -- see our Compaq Stock Decoder.

For links and more detail on HP stock history, see our HP Stock Decoder

Note: Stock plan administrators and stock brokerages vary (sometimes dramatically) in how they make gain/loss and cost basis calculations and in what they report to the IRS. Each of the 236 NYSE member firms (and others around the world) is expected to read SEC filings, analyze corporate actions, and update the records they maintain on behalf of their clients.

The black entries in the table below are from the online system available to customers of broker Charles Schwab & Co. -- which does not cover events before 1987.

The blue entries were developed from reports by members of the Tandem Alumni Forum and contemporaneous news stories. Given Tandem's high growth rate, there must have been earlier stock splits. (EDGAR, the SEC's searchable online database, includes SEC filings from some companies back to 1994 and from all companies only back to May 1996.)