As global growth slows and the world economy teeters on the verge of a new trade-led Cold War, it’s only natural for investors to think about safe havens. They may be surprised to find that the safest haven in European stock markets this year has been…Russia.

The RTS index is up 17.8% for the year-to-date, the best-performing major index in Europe, ahead of the German DAX with 14.7% and the Swiss SMI with 14.0% (the RTS is dollar-denominated index, so it’s not as if those gains have been achieved by ruble devalation). Even more surprising is that it’s also the best perfomer on a three-year view, having risen 41% (the Euro Stoxx 600 is up 12% over the same period).

The RTS even managed to stay in the green on Monday, a day when stocks from Shanghai to Wall Street all tumbled more or less in sync at the prospect of the world’s two largest economies descending into an all-out trade war.

As a result, it’s underperforming Tuesday – as havens often do on up-days – rising only 0.2% by mid-morning in Europe, compared to a 0.3% rise for the Euro Soxx 600 and a 0.5% rise for the FTSE. Germany’s Dax was up 0.6%.

There is a simple explanation for this, and – unfortunately for investors – it’s one that suggests that outperformance may be hard to sustain. Russia’s stock market, like its economy in general, is driven by the oil price, despite endless promises over 19 years by President Vladimir Putin to diversify the economy. Past experience suggests that it will struggle to stay elevated if a trade war slows the global economy and crushes demand for oil.

Oil and gas groups, such as Gazprom (MCX:GAZP), Rosneft (MCX:ROSN) and Lukoil (MCX:LKOH), dominate the index, and as long as they can avoid egregious acts of value destruction (such as throttling Ukraine’s gas supplies to make a political point, or buying favored oligarchs out of companies such as TNK-BP) , they can hardly help but make money. Lukoil, the best run of the three, raised net profit 48% last year to over $9 billion.

As long as high oil prices support the ruble, that also raises the value of companies whose income streams are in rubles – most notably Sberbank (MCX:SBER), Europe’s largest bank, and internet company Yandex (NASDAQ:YNDX).

Oil prices are riding high at the moment because Russia is – notionally – keeping production off the market in coordination with Saudi Arabia and OPEC to keep the market balanced. The risk of conflict between the U.S. and Iran is also helping.

However, Russia is visibly less committed to the deal than Saudi Arabia – its Energy Minister Alexander Novak distanced himself at the weekend from the Saudi position that there was a consensus in favor of extending the deal when it expires in June. Igor Sechin, the Rosneft CEO widely seen as the most powerful man in Russia after President Vladimir Putin, has argued that the whole strategy plays into U.S. hands by giving it a bigger share of the global oil market.

Those who have stuck with Russian stocks throughout the lean years since the annexation of Crimea have earned this moment in the sun. Extending it will still require a supreme balancing act from those who control the country’s oil and gas taps

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This article by Geoffrey Smith was originally published at Investing.com