registery consolidation speculation, page-2

"Stockland, Westfield and Valad, among others, each have more than 1.5 billion units on issue and could look to reduce that in coming months."

I read somewhere that companies can do a buy back when too many shares are on issue. I assume this is what is meant by the above comment.

Can someone tell me how that works and if you are a holder why you would do it?

Thanks
Leane