If Sin Tang were open to pursuing a takeover for SPH they would have had it ready to roll out yesterday; they would have recognised that it was likely that SPH would reject their debt and equity underwriting proposal and rolled it out ASAP before Xstrata got to 50%.
It now looks like Xstrata is the only play for shareholders; I'd say it is an extremely low possibility that Sin Tang will counter-bid. They will be happy to sit on their 13% and negotiate off-take should Xstrata gain control.
I think the time has come to accept Xstrata's bid, noting that the SP will likely drop substantially come Monday, or even before if Xstrata don't look like approaching 50%.
If Xstrata don't look like getting to 50% then the SP will fall as scalpers exit. I would expect to be unable to sell around $2.90 on market per today's trading; as the week wears on the SP will slide.
SPH Price at posting:
$2.95 Sentiment: Sell Disclosure: Held