Neilson joined ROC as CFO in 2007 before being elevated to the CEO's role when Hong Kong-listed investor Fosun International acquired the company in 2014.
Before that he held commercial, finance and business services roles at Caltex Australia, Credit Suisse First Boston in London and Arthur Anderson in Sydney.
Santos has another credit rating review looming, and the consensus among 14 investment analysts covering the company polled by London's Financial Times is that they maintain their ‘hold' position, which has been the case since sentiment over Santos deteriorated on August 21.
That was two days after Santos revealed a half-year loss of $US1.04 billion and a $1.05 billion impairment on Gladstone LNG.
Its shares fell by as much as 2.7% after wrapping up its $A2.5 billion equity raising in December, though Brent had also dropped 4.1% overnight.
Some analysts are concerned the company will need similar drastic action to shore up its balance sheet, which still includes some $6.5 billion worth of debt.
Others say the company should be broken up, and there have been reports that at least one major bank is running the numbers on this scenario as investors may see better bang for buck that way.
China moves
China, always on the lookout for more gas and keen to take equity positions in LNG projects and companies, looms large as a potentially significant player as some, including Argonaut Securities founder Eddie Rigg, call for Santos to be broken up.
RBC Capital Markets analyst Ben Wilson said the appointment of Neilson - who managed ROC's portfolio of assets in China, Malaysia, and Australia and sought new investment opportunities for the Chinese parent - would be particularly prescient given China's involvement in Santos' shareholding.
"We think that Mr Neilson, along with sound financial management experience, will bring valuable insight into Chinese oil and gas investment strategy, which is particularly relevant to Santos given that it counts China's ENN Group as a 12% shareholder," Wilson said.
"The company is highly levered to oil price given that it is close to its free cash flow breakeven point and remains on the cusp of ceding its prized investment-grade credit rating should oil prices continue to slide."
Wilson also warned that with first redemption date of Santos's € 1 billion hybrid coming up in September 2017, if Santos does not replace the hybrid with some of its syndicated bank debt liquidity buffer, it will face a material step-up in interest costs.
"We remain cautious on Santos despite its recent, material share price re-rating, as reflected in our Sector Perform recommendation," Wilson said.
"We are keen to see evidence of the sustainability of recent cost-cutting measures, particularly as they relate to 2P reserves and producibility of assets relative to contractual commitments."
China's ENN Group, via its Shanghai-listed subsidiary ENN Ecological Holdings, emerged as Santos' key strategic shareholder in March when it agreed to acquire China's largest private equity group Hony Capital's shareholding in the Adelaide-based oiler for $US750 million.
In turn, Hony agreed to subscribe to a private placement of what appeared to be about 15% of ENN-EC's capital, paying about $380 million.
Santos welcomed the trade buyer displacing the private equity shareholder, calling ENN a "shareholder with obvious knowledge of the gas business across the region".
However, the shareholding will continue to remain escrowed until November 9, just before Neilson starts at Santos in December.
ENN, China's largest private gas group with operations in nearly 150 cities and more than 11 million customers, is building the country's first private LNG receiving terminal in Zhoushan, Zhejiang Province, with a three million tonne capacity once the first phase is complete in 2018.
However, ENN has come under pressure from regulators to justify its 11.7% stake in Santos, with the Shanghai Stock Exchange asking its parent company to provide more information on due diligence it performed on the deal.
"Santos has been reporting huge losses in recent years and your company has now incurred a huge loss just two months after the transaction," China's market regulator said in an inquiry letter posted on its website last Friday.
"Considering the low level of crude oil prices, please disclose the reasons for this major investment," the bourse's regulators asked.
