Resources investors would do well to sit tight

Last week's big slide in the oil price came in the wake of a hit to mining stocks caused by China's surprise hike in interest rates, the first for nine years.

Commodity-related companies have been doing extremely well this year on the back of strong Chinese demand for their output. Any sign of the much forecast hard landing for the world economy, especially one led by China, would prompt a collapse in so-called deep cyclicals - such as mining stocks.

Given that I have been pushing the merits of both oil and other commodity-related stocks, it is time to revisit those recommendations.

The call on familiar UK-listed stocks such as BP and BHP Billiton is a relatively straightforward one. These types of companies produce something where the simple laws of supply and demand are likely to keep prices higher for longer than the market currently expects.

Oil is an obvious example, where prices have already exceeded all forecasts and, more importantly, are likely to do so for some time.

The claim that the expert forecasters are all wrong might look a touch extravagant. The underlying logic, however, is simple.

We know an awful lot about oil supply. All those analysts spend most of their time making guesses about something that is actually pretty fixed: the known productive capacity of the world's oil fields. The tricky bit is estimating likely oil demand.

What we do know is that, for the most recent past, the demand for oil has been roughly equal to the global oil output. Actually, the rise in oil prices could well have arisen because of an excess of oil demand relative to its price; equally, there could be a speculative element to the run up in prices.

What matters, it seems to me, is whether we think the factors that have kept prices high are likely to persist. Given the relatively fixed nature of oil supply (if anything, this seems set to decline over the medium to longer term), it all comes down to forecasts for demand.

On anything other than a particularly bearish view of China and the world economy, it seems sensible to expect demand to remain high, even if global growth does slow next year. This year has seen the fastest rate of growth for the world economy in nearly three decades so some easing back does seem inevitable.

How much speculative froth is in the oil price? This is always impossible to tell until after the event but, in my view, is unlikely to have been worth more than around $10 (€7.73) per barrel on the price. Crucially, this leaves the "fundamental" level of oil prices still well in excess of the long-term oil price assumptions embodied in most analysts' valuation models.

Two years ago, most oil company analysts based their share price valuation targets for oil companies on a long-term oil price forecast of around $18-$20 per barrel.

Inevitably, these long-term forecasts have crept up, but not to anything like current levels of the oil price.

My best guess is that oil company valuations are still being based on an oil price assumption of something like $20-$25 per barrel.

Essentially (with only a bit of over-simplification), any positive bet on oil companies from here must imply that long-term oil price assumptions embodied in company valuations are too low. I would make that bet.

The analysis of metals and mining companies turns on similar considerations, although for many basic commodities there are not so many of the absolute supply considerations that affect oil production.

Mining companies have a habit of over-investing in productive capacity (digging too many holes in the ground) at the top of the demand cycle. This time around, there are some signs of better capital discipline, so the call, as in oil, remains focused on the demand side. And, again, I remain relatively optimistic.

The two companies that I mentioned in February, BHP and BP, have risen, at the time of writing, by roughly 13 per cent and 23 per cent respectively, compared to a rise in the FTSE 100 of around 4 per cent. It is tempting to take profits.

One respected analyst (by me at any rate) recently said that resource-based companies used to be ones that investors should "rent" occasionally, meaning that they should only ever be owned for very short periods of time. But, he goes on, because of all those changes in the supply-demand balance, they are now companies that should be owned strategically, and occasionally rented to others during cyclical downturns. Is this a time to rent out our holdings of oil and commodity stocks?

I am still inclined to hang on to these companies, despite some short-term worries. In fact, I would be tempted to add some very out of fashion names such as Shell, which has risen by "only" 7.8 per cent since February, largely because of concerns about the company's level of oil reserves. JP Morgan, for example, downgraded Shell earlier this month precisely for this reason. But this would be a high-risk bet.

BP looks good for all the reasons mentioned above, plus a few others. It's probable capital spending programme (looking for oil) will be less than Shell's and it will be able to pump more oil and return more cash to shareholders - more than $5 billion in share buybacks this year on top of normal dividends. This is a company that will continue to do well.

If I was forced to divest a part of any holdings of resource-based stocks, I would sell holdings of mining companies before I parted with oil companies. But this would be an explicit "renting out" strategy: any slowdown, no matter how mild, in the world economy has the potential, over the short-term at least, to hit these stocks quite hard.

However, for anyone with patience - and nerves - any decision to hold on to mining stocks will, ultimately, be well-rewarded.