According to the NASDAQ Glossary, ticker symbol extensions are additional letters added to a security identifying it as something other than a single issue of capital stock or common stock. These extensions are known as "fifth-letter identifiers" or "fifth letter codes" for NASDAQ and Over the Counter Bulletin Board stocks. The symbols are "behind the dot" codes for shares traded on the New York Stock Exchange because extension symbols are added after a period after a NYSE ticker name.
Ticker symbols are abbreviations of a company's name, originally developed to transmit stock trade information by telegraph with fewer letters than a full name. The Standard & Poor's Co. brought uniformity to trading symbols by assigning a single letter combination to each company traded on a U.S. exchange. Ticker symbol extensions serve the same function as company name abbreviations, with the Securities and Exchange Commission providing uniform letter extension symbols and definitions for companies, subject to the agency's regulation.
Neutral Symbol Extensions
Ticker symbol extensions have been assigned to every letter from A to Z. One common two-letter extension is .PK, denoting a stock traded on the Pink Sheets, an over-the-counter stock quotation system. While all symbols provide more information about a particular share, some are more benign than others. "A" is a class A share, while "B" is a class B share. An example of a behind-the-dot listing for these extensions is Berkshire Hathaway, which trades class A (BRK.A) and class B (BRK.B) on the NYSE. A company can have voting (J) and nonvoting (K) shares or sell securities with a first (G), second (H) or third (I) convertible bond. Preferred stock can enjoy fourth (M), third (N), second (O) or first (P) preferred status. Shares can also be new (D) or foreign (F).
Added Rights Symbols
Certain symbols grant security holders additional rights in addition to a common share. Not surprisingly, the extension symbol for "rights" is R. Since all symbols are abbreviations, to find what rights are given with a particular security, potential purchasers need to read company SEC filings and press releases for more details. Investors can purchase shares the following symbols: of beneficial interest (S), with warrants or with rights (T), units (U), when issued and when distributed (V), and with warrants (W). Seeing an "X" as the last identifier letter denotes a mutual fund.
The two biggest potential warning symbols are E (delinquent in SEC required filings) and Q (bankruptcy). An E could be a simple filing mistake remedied with a hurried filing, or it could be what Worldcom received on its way from its NASDAQ listing of WCOM to WCOME, then to trading on the OTCBB as WCOEQ in less than 30 days in 2002. When GM filed for bankruptcy in 2009, it changed the name of the "Old GM" to Motors Liquidation Co., left the NYSE and got the ticker symbol MTLQQ on the Over The Counter market.
Remaining single extensions
Rounding out the alphabet of one letter extensions is "C," given when the issuer has been granted an extension of qualification standards by NASDAQ for a limited time. Miscellaneous situations get an L or a Z, and Y denotes an American Depositary Receipt.
To provide global market information coverage, Reuters news service pairs up thousands of stock symbols and more than 100 different stock exchange designations with its Reuters Instrument Codes. These RICs can appear in headlines, captions, titles, stories and metadata, according to the company. Confusion can occur when RICs are not removed before general publication. Microsoft's NASDAQ symbol becomes MSFT.O, with O being the RIC symbol for NASDAQ. The symbol does not mean Microsoft is offering second preferred stock, the SEC fifth-letter identifier for O. Thankfully, RIC does not designate any exchange with an E, and the Q code identifies the Japan OTC market. While Bloomberg uses a set of proprietary exchange and country codes, none of them is a single letter.