If they want to use shares to buy a company, then if their shares fall it will make it harder for that takeover to proceed. The market's probably getting a bit of indigestion as regards to the size of the predatory move.
Globally, steel shares are up as some people are pricing in potential takeovers. Consolidation will help shift the balance of power against the raw materials suppliers.
At face value, Patrick shares should start higher. The question is whether the new Toll entity gets a re-rating in the market after the acquisition on synergy benefits, or whether debt levels will be a bigger concern.