Ask Colin

Why is there a difference between the number of shares a company has issued and the number that are quoted on the ASX?

There are a number of reasons why securities issued by companies are not listed.

The example you quoted was Occupational and Medical (OMI). I looked it up in the Unlisted Company Securities table in the back of Shares magazine. For OMI it shows only one type, called "restricted". I think you are right in assuming that these are in escrow, which probably means they are vendor shares in the float and may not be traded for a period.

Looking through the list in Shares magazine, other typical unlisted securities are:

Ordinary shares that the company has not applied for listing for various reasons - a common one is that they may be issued and traded only on overseas markets. Eg. Anglogold (AGG).

Options of all kinds, including employee options.

Employee shares of various kinds.

Some kinds of preference shares, including convertible ones.

Some kinds of contributing (partly paid shares).

Deferred delivery shares (tends to be technical and short term).

With some of these, the company may take the view that there is no real need to provide a secondary market, so they have not applied for listing.