LA PAZ, Bolivia — Argentina’s currency has plunged, setting off global worries about developing economies. Brazil is struggling to shake concerns over years of sluggish growth. Venezuela, which sits atop the world’s largest oil reserves, has one of the world’s highest inflation rates. Farther afield, countries like Turkey and South Africa have watched their currencies suffer as investors search for safer returns elsewhere.

And then there is Bolivia.

Tucked away in the shadow of its more populous and more prosperous neighbors, tiny, impoverished Bolivia, once a perennial economic basket case, has suddenly become a different kind of exception — this time in a good way.

Its economy grew an estimated 6.5 percent last year, among the strongest rates in the region. Inflation has been kept in check. The budget is balanced, and once-crippling government debt has been slashed. And the country has a rainy-day fund of foreign reserves so large — for the size of its economy — that it could be the envy of nearly every other country in the world.

“Bolivia has been in a way an outlier,” said Ana Corbacho, the International Monetary Fund’s chief of mission here, adding that falling commodity prices and other factors have downgraded economic expectations throughout the region. “The general trend is we have been revising down our growth forecast, except for Bolivia we have been revising upward.”