We normally think of Australia as the “lucky country” but that label is surely better applied to the US today.

You could hardly envisage a more benign backdrop for its economy and stock market than the current environment of tumbling energy prices, low inflation, narrowing deficits, competitive industry, a popular currency and consequently lower-for-longer interest rates.

The frantic shuttle diplomacy in the run up to last week’s Opec summit in Vienna illustrated the pain being felt by the world’s less favoured nations — those like Venezuela and Russia which simply can’t balance the books at a $75 oil price. The meeting showed how difficult it can be to persuade individual countries to work together if doing so runs counter to their own self-interest.

It may be beneficial to Opec as a whole to curb production in the face of surging US shale oil output and flagging global energy demand, but individual countries may quite rationally decide it is better to keep the oil flowing to protect their market share. If you have built up enough foreign currency reserves in the good years (as Saudi Arabia has) and you want to make life tough for your new rivals in the marginal oilfields of North Dakota, you might feel a couple of years of cheap crude is a price worth paying.

The excess supply created by America’s shale revolution has been disguised in recent years by capacity reductions in war-torn countries such as Libya. But the producers’ luck has run out this year as supply has picked up around the world even as China’s slowdown and stagnation in Europe and Japan has reduced demand.

The jockeying for position by Saudi Arabia and others might sound like a game, but it really matters. With world oil exports amounting to around 40 million barrels a day, the $40 drop in the oil price since June represents a transfer from oil exporters to oil consumers of more than $400 billion a year.

US consumers have an extra $70 billion in their pockets, money they used to spend on fuel and can direct towards eating out, buying electronic gizmos or going on holiday. Even with the usual lag before consumers see the benefit of falling petrol prices, we are starting to feel the impact.

Last week’s revision to third quarter US GDP, from 3.5 per cent to 3.9 per cent, was in part a reflection of more confident consumers with higher disposable incomes. Americans’ increased purchasing power could hardly have come at a better time, as the annual Black Friday and Cyber Monday consumption splurge gets under way.

With consumption accounting for two-thirds of the US economy, this is one key benefit of the oil price slide. But it is not the only one. Cheap energy is rapidly replacing cheap labour as the key differentiator between countries competing for investment in a global marketplace.

As emerging markets’ wage bills rise, America’s energy advantage becomes ever more significant. Europe, which missed out on the first big shift, looks like being squeezed as badly by the second. No wonder companies like BASF are choosing to build any new chemical capacity on the shores of the Gulf of Mexico and not the banks of the Rhine.

The third key benefit of cheap oil for the developed world, and America in particular, is the downward pressure it applies to an inflation rate that might otherwise have started to pick up on the back of a recovering housing market and falling unemployment. Low inflation is providing the cover needed by central banks such as the Fed to keep monetary policy much looser for longer.

Even when rates do start to rise, probably in the middle of next year in America and later still in the UK, the trajectory will be shallower and the end point lower in a world of cheap energy. The falling oil price is not unqualified good news.

For every consumer business looking at a Thanksgiving bonanza there is an over-borrowed oil drilling company that took advantage of super-cheap debt in the junk bond market and is now wondering how it will pay the coupon. Energy companies represent 16 per cent of the US high-yield bond market, compared with 4 per cent a decade ago.

Junk bonds can be the canary in the mineshaft for the stock market. But that is a problem for another day. In the short-term, the US market’s string of new highs is a logical response to the emergence of the new lucky country.

— The Telegraph Group Limited, 2014