A worker at a nuclear power plant owned by0xA0Tokyo Electric Power Co. the best-performing international stock of 2013’s0xA0first half. Photograph by Toshifumi Kitamura/Pool via Bloomberg

The first six months of 2013 were a great time to be an electric-car aficionado who owns an oil well. It was a lousy time to be a gold miner and it remained an awful time to be a Spanish banker. That is, at least, if you judge by the performance of financial markets.

The arrival of July seems a good time to check in on Bloomberg’s list of the Best and Worst Investments. (We’re following the same criteria as the 2012 version .)

The Best U.S. Large-Cap Stock is Tesla Motors. a company with huge ambitions in electric vehicles but no profits until this year. It’s up 217 percent through the end of June and rocketed another 12 percent in the first week of July.

The Worst U.S. Large-Cap Stock is Newmont Mining Corp. go, a gold mining company that plunged 35.5 percent in the first half of the year. The stock fell alongside the price of gold. which was down 26.3 percent as of June 28 and off 23.5 percent as of July 11. Gold was not the Worst Commodity of 2013’s first half — that would be silver. which has dropped 34 percent year-to-date. The Best Commodity this year is oil, up 14 percent through July 11.

Outside the U.S. the Best International Stock * is literally recovering from disaster. Up 149 percent in the first half of the year, the Tokyo Electric Power Company. or Tepco, was the operator of the Fukushima atomic power station destroyed in Japan’s 2011 earthquake and tsunami. Now, it wants to restart one of the plants idled after the tragedy.

The Worst International Stock * so far this year is Spanish bank Bankia SA. down 88 percent. Bankia was also the worst international stock of 2012. as it was pummeled by Spain’s real estate collapse.

Such consistency from year-to-year is rare. Few of last year’s best investments were able to stay on top. Apple. up 31 percent in 2012 and down 20 percent this year, is a classic example. Last year’s worst U.S. large-cap stock was Hewlett-Packard. but it’s up 86 percent in 2013.

Wall Street pundits frequently claim that it’s a stock picker’s market. The volatility of these rankings is yet another demonstration of how difficult — some would say impossible — these stock pickers’ tasks are.

(*The criteria for International stocks was inclusion in the MSCI emerging and developed market indexes.)

This essay originally appeared in Bloomberg.com’s weekly personal finance newsletter, Wealth Watch. Sign up here .