The scrip of Singapore?s premier healthcare firm Parkway Holding showed its highest advance for 12 years and touched its two-year best closing price of S$3.71, up 23% over the previous close at the Singapore Stock Exchange.

The stock was suspended from trading on Friday after Malaysian government?s investment arm Khazanah Nasional Bhd offered S$1.18 billion ($841 million) to up its stake to 51.5% from the current 23.3%. The last time Parkway scrip crossed the current price levels were in November 2007. The jump of 23% over the previous close is the highest since 1998.

The offer price of Khazanah at S$3.78 reflected 25% premium over the previous closing share price of Parkway. If Khazanah’s offer is accepted, the current share holder Fortis Healthcare, with its 25.37% stake in the company, would lose its status as the largest stakeholder in the company. Fortis promoters Malvinder and Shivinder Singh aimed to create a unique global healthcare model using Parkway as the platform. This has led to speculations on whether the Singhs would now launch a counter-offer to beat the Khazanah?s bid.

Many financial experts without ruling out the possibility of a protracted bidding war, have cautioned shareholders about a possibility in which the Parkway’s share price would surge ahead of its underlying business fundamentals.

Already, the original valuation by Fortis in March where it paid over $670 million to acquire just over 23% in Parkway (close to $1 million per bed) was considered expensive by many experts.

However Fortis has been accumulating shares since March and at last count had a stake of 25.37% in Parkway. The latest of Fortis buys into Parkway came just days before Khazanah made the offer. Fortis bought an additional 350,000 Parkway shares at an average price of S$3.1477 on the open market, raising its stake to 25.37% from 25.34% previously, Parkway said in a disclosure statement to the Singapore Exchange on Monday.

This buy took place last week before Khazanah, which also owns about a quarter of Parkway, made $835 m offer to gain majority control of the Singapore firm. Shivinder Singh refused to give away any clues maintaining on Monday that he has been legally advised to keep silent. Meanwhile Khazanah appointed leading Singapore banks? DBS, OCBC and UOB as joint arrangers of financing for its offer to buy a controlling stake in healthcare group Parkway Holdings.