JACKSON HOLE, Wyo. Every August, the world’s financial markets shift their attention from the centers of global commerce – New York, London, Tokyo – to a mountain valley in northwest Wyoming. On Friday, they will hear a speech by Federal Reserve Chairman Ben Bernanke.

So how did Jackson Hole, Wyo., come to wield such outsize importance in global economic affairs?

In a word, trout.

For four years starting in 1978, the Federal Reserve Bank of Kansas City hosted an annual conference at different sites and different times of year.

Officials at the bank pondered how to draw bigger names and more attention to the yearly confab. That’s when they set their sights on Paul Volcker, then chairman of the Federal Reserve.

They decided to pursue Volcker by dangling the prospect of one of his favorite pastimes: fly-fishing. They needed to find a sure-fire trout-catching spot somewhere in the Kansas City Fed district, which covers Colorado, Kansas, Nebraska, Oklahoma and Wyoming, as well as northern New Mexico and western Missouri.

They considered somewhere in Colorado. But a fly-fishing expert said Colorado’s waters were too warm for trout in August. Go farther north, he said. Go to Jackson Hole.

And what’s been known since 1982 as the Jackson Hole Economic Symposium took its place in economic lore.

Jackson Hole isn’t even a town. It’s a valley. The Fed conference occurs in a lodge in Grand Teton National Park, about 50 miles south of Yellowstone National Park.

140 powerful people

The event now draws 140 people every year, including some of the biggest names in economics and finance. They come to enjoy breathtaking views of the Grand Teton mountain range and Jackson Lake, to hike and fish and to engage in intellectual combat in the halls of the Jackson Lake Lodge.

One annual tradition is the Friday night barbecue. There, some of the world’s most high-powered economists don cowboy hats, string ties and other Western gear and sometimes join in a line dance.

At each year’s Jackson Hole conference, the Fed chairman is a focal point. Investors started focusing especially intensely on Jackson Hole after Bernanke used his remarks there in 2010 to lay out the Fed’s policy options.

The speech – and growing evidence that the economy needed help – ignited a 28-percent stock market rally over the next eight months.

Friday morning, attention will again be riveted on Bernanke’s annual speech.