Ann: Trading Halt , page-5

"The offer price under the SPP will be at a price equal to the lower of the price of the Institutional Placement less the declared FY10 dividend or a 2.5% discount to the 5 day VWAP prior to the opening of the SPP. Shares issued under the SPP will not participate in Macarthurs FY10 final dividend"

If it's only a 2.5% discount, I won't bother, unless the market really rallies between the opening and closing of the SPP.