Ann: Downer completes Retail Entitlement Offer, page-4

9 million shares in the hands of the underwriters represents only 3-4 days average trade, so I do not expect a big impact on sp - though you might be able to pick up a few more between $4.10 and $4.20 over he next fortnight.

The real problem here is that it is "money for jam" for the underwriters, whereas these shares should have been available to existing shareholders. A best practice approach (or even just a fair practice approach) would have allowed existing shareholders to subscribe for more than their rights allocation, and be allocated shares from any shortfall. Not hard to do. Fair to loyal shareholders.
Very poorly done Downer Board!