They reckon past performance is no indication of future achievement.
Try telling that to long suffering investors in OZ Minerals (OZL). After years of disappointments, scandals, previously unknown debts hammering its cash reserves and a firesale of most of the assets to a Chinese Government owned company, OZ this year has notched up what could only be described as a shocker.
Adding insult to injury, the company recently delivered earnings results that were far worse than anyone anticipated which the board embellished by warning shareholders the year ahead would be "difficult".
The theme continued this morning. Following earlier production downgrades as a result of problems at its ageing Prominent Hill mine in South Australia, the company held out the promise of better times ahead.
Sadly that has not come to pass. The task of moving waste from Prominent Hill has resulted in copper production falling as much as 14% to potentially be as low as 70,000 tonnes.
Even more concerning, costs have risen substantially, possibly to as high as US205c a pound, way above its previous upper range of US180c a pound.
Not surprisingly, alarmed shareholders reacted badly with the stock dropping 9% in early trading.
OZ has pinned its hopes on the Carrapateena mine in South Australia which still is several years off production and draining the company of cash.
After selling its assets to the Chinese in 2009, OZ had about $1 billion in cash apparently earmarked for acquisitions and expansions. Less than half that remains.
A fortnight ago, speculation emerged that the newly merged Glencore Xstrata had secretly assembled a 10% holding in OZ and was preparing to pounce.
That subsequently was hosed down by OZ, given the London firm would be obliged to declare any interest above 5%. Glencore Xstrata also is the subject of undertakings to China to decrease its copper exposure as a condition of the merger.
But there may be some truth lurking behind the rumour. OZ is extremely vulnerable right now with gold and copper prices weak (see Tim Treadgold's Commodity prices can only go up).
Many analysts, however, believe copper prices could rebound in 2016, just as Carrapateena is coming on stream and with half of OZ's assets highly liquid – with cash and equities – the company clearly would be on the acquisition radar screens.