Why would a company have 2 listings on the same exchange?

Question

An example would be Cardno Ltd which has:

1. CDD.AX - http://investing.businessweek.com/research/stocks/snapshot/snapshot.asp?ticker=CDD:AU
2. CDDN.AX - http://investing.businessweek.com/research/stocks/snapshot/snapshot.asp?ticker=CDDN

I can see that the CDDN has no updated info... does that mean its not active? But will there ever be a time when a company has 2 or more active listings on the same exchange? If yes, what would be the difference?

Please note that I do not have a full/official background for trading/financial markets.

Answer 1

A company can issue different kinds of shares. For example, some kinds of shares may get preference in dividends or payment in event of (company) bankruptcy. Preferred shares are an example of this. A company might have several kinds of preferred shares and a 'common stock'. Here is a good explanation. See too the Wikipedia article about preferred stock.

Toronto-Dominion Bank (TD) is an example of a company that has fourteen different preferred share issues, each with its own listing on the Toronto Stock Exchange (TSE) and symbol. TD has one kind of common stock, which is also listed on the TSE. However, TD common equity trades much more actively than the preferred shares. Remember that preferred stock is a different security type than common stock e.g. common has voting rights, preferred does not.

Answer 2

Some companies like Royal Dutch Shell have multiple share classes to suit the tax regimes in Holland and the UK the A shares have dutch withholding tax applied and the B shares dont.

Also some split capital investment trusts have multiple share classes http://www.trustnet.com/Education/Split.aspx?ms=1