Tinkler wealth plunges more One-time billionaire Nathan Tinkler's wealth has taken a new battering after shares in his main investment Whitehaven Coal hit near four-year lows. The embattled entrepreneur's 21 per cent stake in Whitehaven had plunged to $570 million in value on Friday from nearly $1.2 billion last April. The fall came on the same day the 36-year-old's luxury jet and helicopter were put up for sale in advertisements paid for by receivers seeking nearly $14 million. Australia's former youngest billionaire's business empire is debt-laden and struggling for solvency with various companies and subsidiaries placed into receivership and liquidation in recent months. Whitehaven shares closed 12 cents, or 4.3 per cent, weaker at $2.68. That compares to $5.58 last April when a merger with Aston Resources made Mr Tinkler its largest shareholder. Analysts thought Friday's fall was connected to Whitehaven's own troubles including forecasts this week that the second half of 2012-13 would be no better than the $47 million first half net loss it posted. However it again put pressure on Mr Tinkler, who is believed to hold about $700 million in debt, which was about what his Whitehaven stake was worth at the start of trading on Friday. One of his companies, Mulsanne Resources, is in liquidation after failing to pay for a $28.4 million share placement in listed coal company Blackwood. One analyst said he did not think Mr Tinkler's lenders, such as hedge fund Farallon Capital, would call in their loan as has been speculated. He thought it would be better selling shares to new owners with steadier hands, something Whitehaven chief executive Tony Haggarty has previously said would be ideal. The analyst, who did not want to be named, said he thought investors were spooked by Whitehaven's negative outlook for coal for the rest of the year and Mr Haggarty's resignation. "They are not making any money," he told AAP. Their statement at face value reads that it is going to be as bad in the second half as the first half ... they set expectations very low but coal prices are up on the first half.