It’s hardly surprising that the total net worth of the members of BRW magazine’s Rich 200 list fell by $25 billion in the last 12 months. What is surprising is that it didn’t fall further.

Yes, $25 billion is a big number and an awful lot of money. Yes, the number of billionaires on the list has dropped from 38 to 28. Yes, most of our richest entrepreneurs — including new number one Anthony Pratt, James Packer, Kerry Stokes and Frank Lowy — have lost a bundle. And yes, the cut-off for inclusion has fallen from $200 million to $150 million.

But the $25 billion decline in the total net wealth of the members of the list represents a decline of just 17% on last year’s total of $139 billion. By comparison, the All Ordinaries fell more than 36% from mid-May 2008 to mid-May 2009.

Based on BRW’s figures, it appears that as a group, the members of the Rich 200 have outperformed the ordinary investor to an impressive degree.

Still, not everyone has had a great year. Perhaps the biggest shock on this list is the decline in the fortune of James Packer. Back in 2007 (the last year I edited the Rich 200) I was responsible for Packer’s valuation. We did our analysis and came up with a figure of $7.4 billion. We submitted this to Packer via his personal assistant, expecting to get no reply (as usual) but were surprised to receive an email saying we had consistently over-stated the Packer fortune and he was worth $7.25 billion.

Since then, Packer’s wealth has plummeted, dropping from $6.1 billion to just $3 billion in 2009. Given his stakes in public companies such as Crown, Consolidated Media Holdings, Sunland and Challenger Financial Services are around $2.7 billion today (compared to around $4.2 billion last year), it stands to reason that the Packer family’s private assets — such as the private equity firm Arctic Capital; the funds management business Ellerston Capital; and cosmetics company Jurlique — have fallen in value from $1.9 billion to just $300 million.

Another shock is the movements in the fortunes of two of the key figures at struggling media group Fairfax Media. The valuation of chairman Ron Walker has surged from $427 million to $768 million (apparently due to his investments in residential land and property developments in Melbourne) while the valuation of major shareholder and director John B. Fairfax has dropped from $1.32 billion to $618 million, mainly due to Fairfax’s sagging share price.

There were some surprising increases in valuations too. The rise in the value of Sydney apartment king Harry Triguboff (from $3.25 billion to $3.7 billion) is impressive, given the poor performance of the NSW economy and Sydney’s property market in the last 12 months.

The jump in the valuation of Queensland mining magnate Clive Palmer – from $1.5 billion to $3.4 billion — is another shock, given the performance of the commodities sector in the last 12 months and the fact he was forced to put the $5 billion float of his company RDI on hold. Still, Palmer has argued long and hard that BRW has undervalued his fortune and his valuation has now more than doubled.

It is worth noting that BRW’s valuation is a long way from that of US magazine Forbes, which released its list of the 40 richest people in Australia earlier this month and valued Palmer at just $535 million. While this seems ridiculously low, it does highlight the fact that there are some big discrepancies between BRW’s valuations and those of Forbes, including James Packer ($4 billion in Forbes compared with $3 billion in BRW), Frank Lowy ($3.8 billion compared with $4.2 billion) and Harry Triguboff ($2.5 billion compared with $3.7 billion).

All of which shows that valuing the rich is an extremely tough job. Indeed, yesterday Malcolm Turnbull protested his inclusion in the Rich 200 (with a fortune of $178 million), declaring BRW had “no idea” of his net worth and claiming the magazine had not consulted him about the valuation (this is garbage – the magazine has a strict policy of trying to contact each Rich 200 member at least twice and Turnbull’s media team were well aware of his inclusion).

“I don’t go around calculating my net worth and it would be hard to calculate it anyway, because what are various assets worth at any given time?” he told reporters.

Turnbull has a point, of course — valuing a person’s fortune is difficult, particularly in this economic climate where asset values are so volatile.

But that’s exactly what makes BRW’s Rich 200 such as fascinating read each year and the 2009 edition is no exception.