For most investors, the major story of 2015 was the expectation and eventual fulfillment of a rate hike, signalling the start of tightening monetary policy in the United States. This policy is divergent to those of other major central banks, and this has translated into considerable strength and momentum for the U.S. dollar.

Using the benchmark of the U.S. Dollar Index, a comparison against a basket of major currencies, the dollar gained 8.3% throughout the year.

Despite this strength, the best performing currency in 2015 was not the dollar. In fact, the top currency of 2015 is likely to be considered the furthest thing from the greenback.

Bitcoin, a digital and decentralized cryptocurrency, staged a late comeback in 2015 to overtake the dollar by a whopping 35% by the end of the year.

Bitcoin is no stranger to extremes. During the year it came into the mainstream in 2013, Bitcoin gained 5,429% to easily surpass all other currencies in gains. However, the following year it would become a dog, losing -56% of its value to become the world’s worst performing currency in 2014.

The second best performing major currency, relative to the USD, was the Israeli shekel. It gained 0.3% throughout the year, and the Japanese yen (0%) and Swiss franc (0%) were close behind, finishing on par with how they started the year.

The world’s worst performing currencies are from countries that were battered by commodities or geopolitical strife.

Ukraine’s hryvnia fell -33.8% in the aftermath of Crimea. Brazil’s real (-30.5%), the Canadian dollar (-15.9%), Russian ruble (-20.8%), and South African rand (-26.7%) all lost significant value in the purging of global commodities. Gold finished the year down -10%, and silver at -11%.

And as China devaluation accelerates, Bitcoin has been surging since the start of the year...