Stock markets can go up as well as down, as 2012 has proved. But...
there are plenty of folks who can conspire to produce eye-watering losses for themselves even against the positive backdrop of a rising market.
The year has been notable for some collapsing fortunes and reputations. Investments have gone wrong, dodgy practices have been exposed and bankers have paid for costly demergers on the domestic, if not professional, front. So here is our list – not nearly definitive or scientific – of who lost their shirts and how in 2012.
As was gloriously revealed in the libel courts, Nat Rothschild will pay good money for a thrashing. That line has proved to be true in a corporate sense too. The financier, who in January regaled Mr Justice Tugendhat with the colourful tale of being "beaten by a 25-year-old banya keeper man … before jumping into ice cold water" at a sauna, started the year with a fortune of £1bn, according to this year's Sunday Times Rich List. That may need revising.
Shares in his mining creation Bumi have slumped by almost 70% this year, while those in electricals group Volex (where he's a big investor) have lost by 75%. The value of Rothschild's oil group, Genel, has also slipped by 6%, leaving predictions that Nat will become the "richest Rothschild of them all" looking somewhat bullish.
When Facebook floated in May, the shares of 28-year-old founder Mark Zuckerberg were worth just south of $19bn (£11.75bn). He is now $5bn less rich after the market told him he'd overcharged by 28%. The slump wasn't a big surprise as it's still not clear to anybody born before 1990 how the company will generate enough profits to justify its hefty valuation.
There has also always been an army of willing sellers of the shares within the company itself.
Or as Zuckerberg candidly put it: "We're going public for our employees and our investors. We made a commitment to them when we gave them equity that we'd work hard to make it worth a lot and make it liquid, and this IPO is fulfilling our commitment." They sold.
Last year the former Barclays banker was supposed to be worth £300m. No longer.
That figure halved in 2012 after his marriage to Diana – which had reached its "natural end" a couple of years ago – reportedly ended in divorce.
Jenkins now seems to be consoling himself in the arms of the model Elle Macpherson, while his 37-year-old socialite former wife, who arrived penniless in Britain in 1993, instantly became one of Britain's richest women.
That seems like a reasonable reward for introducing her husband to Sheikh Hamad bin Jassim bin Jabr al-Thani, a Qatari prince and manager of the nation's sovereign wealth fund who invested £8bn in Barclays. Arguably, it saved the bank from a state bailout.
He may possess a name that would suit some Vegas card sharp, but Carlos Slim is actually the world's richest man.
He's just less rich than he was, after a year in which two European investments have slumped in value by about €2bn (£1.62bn).
America Móvil, Latin America's largest telecoms operator, which is controlled by Slim and his family, made its first significant investments in Europe this summer, by acquiring about a quarter of Holland's KPN and Telekom Austria for a combined €4bn.
The value of the 23% stake in Telekom Austria has fallen about 42% and the 28% in KPN by about 46%, according to estimates by the asset management group, Bernstein.
Meanwhile in August, Bloomberg estimated Slim's worth had slumped by $1.7bn. The poor lamb is now only worth north of $70bn.
Amazingly, after the clothing label French Connection first came up with its FCUK brand, customers found the gag amusing enough to keep buying the T-shirts for several years.
The shares soared on the back of this marketing triumph until, suddenly, the joke was on the investors.
The acronym went out of fashion and the new ranges never seemed to sell quite as well without a replacement gimmick.
That has been particularly painful for founder Stephen Marks, who owns 42% of the shares. The value of those slumped again last year – this time by 30% – and made Marks £4.8m poorer. For him, it's no laughing matter.
Peter Cummings, the former HBOS banker once considered a genius for lending billions of pounds to people who couldn't pay it back, found another way to lose money in 2012.
He got himself a lifetime ban from the Financial Services Authority for his role in the banking crisis and was £500,000 less rich too, after the regulator clobbered him with a fine.
Cummings remains the only former HBOS banker to be penalised by the City regulator as a result of the near-collapse of the bank which was rescued by Lloyds in September 2008.
The 57-year old Scottish banker believes he's been singled out. He may have a point.
The ENRC "trio"
ENRC shareholders had a terrible 2011 – and the company followed up that performance with another shocker in 2012. The City fretted over the outcome of two investigations – one into allegations of corruption in ENRC's business in Kazakhstan and another into the group's African operations – which are interesting the Serious Fraud Office and contributed to the shares more than halving over the year.
That drop mainly affected the three founders – aka "the trio" – of Alexander Machkevitch, Patokh Chodiev and Alijan Ibragimov, who collectively own about 35% of the shares. Between them, they are now £1.6bn less rich.
Stephen Hester, the boss of mostly state-owned Royal Bank of Scotland, is fond of presenting himself as an everyman ("I'm blue Labour, or pink Tory" he is fond of saying). So perhaps it's not too surprising to discover how pliable he can become after a touch of public opprobrium. Hester responded to public outrage about his bonus in January by (after initial resistance) renouncing it. The sacrifice made him £1m less rich.
Ivan Glasenberg (again)
Ivan Glasenberg, left, who the City widely regards as a world class trader, is becoming a regular in this annual list. He's the largest individual shareholder in commodity trading group Glencore, so his wealth is rather exposed to one stock. Sadly for Ivan, that stock keeps falling – losing 12% this year and marking down his 15% stake by more than £500m.
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