LONDON (Reuters) - Wall Street and oil were the big financial market winners in the third quarter of 2018, while trade tensions, emerging market crises and central bank policy tightening tipped several other assets into bear markets.

Traders work on the floor of the New York Stock Exchange (NYSE) in New York, U.S., September 21, 2018. REUTERS/Brendan McDermid

Brent crude oil LCOc1 gained 3 percent in the July-September period, recently hitting 4-year highs above $82 a barrel as upcoming U.S. sanctions on Iran are expected to dent global supplies. Prices are up 22 percent year-to-date.

The other outperformer is Wall Street's S&P 500 index .SPX, up more than 10 percent since January. It gained 7.7 percent this quarter, setting the record for the longest ever bull market, and also scaling record peaks.

“It’s actually been a U.S. bull market - very little else has done very well,” Guy Miller, chief market strategist and head of macroeconomics at Zurich Insurance Group, said.

“Oil has been one of the few things that continued to move higher. There has been very little else, but having said that, by end of this year other equity markets returns should be fairly decent.”

GRAPHIC: Global market asset performance - reut.rs/2Oi1SFz

The MSCI All-Country World Index .MIWD00000PUS, a barometer of shares in 47 countries has see-sawed since a global selloff in February knocked it off a record high. However it is up 4 percent this quarter, lifted primarily by U.S. gains.

The dollar failed to make much headway following its 5 percent second quarter surge but it held on to those gains, keeping up the pressure on emerging markets. And alongside the greenback moves and the Sino-Chinese trade spat, currency crises in Turkey and Argentina also dealt a blow to the sector.

Those crises pushed investors into dumping emerging assets.

Argentina's peso ARS= led the falls. Down 50 percent over the year, it is the biggest faller this quarter with a loss of 27 percent. Turkey's lira TRY= was a close second, losing 23.5 percent this quarter, and down 37 percent year-to-date. Brazil's real BRL= is down 16.8 percent this year, while South Africa's rand ZAR=, India's rupee INR= and Russia's rouble RUB= are all down about 12 percent.

GRAPHIC: Emerging market currencies vs the dollar - reut.rs/2Oi3MpO

MSCI's emerging stocks .MSCIEF lost 1.7 percent this quarter, down 14.7 percent this year. The index slipped into a technical bear market in mid-August, losing 20 percent since late-January, but has since recouped some of those losses.

Shanghai "A" shares .SSEA are down 20 percent on the year and lost 5.5 percent in the third quarter, as the tit-for-tat trade spat between the U.S. and China escalated.

“What’s happened in the past three months is that worries about trade tensions are more severe...those concerns intensified during Q3. That’s going to carry over into Q4 almost certainly, and probably into 2019 as well,” said Stewart Robertson, senior economist at Aviva Investors in London.

Copper CMCU3 – a proxy for global economic growth - also entered a bear market this quarter, falling 6.7 percent as the fallout of the trade war was expected to hit demand in top consumer China. The metal is down 14 percent this year.

Another metal that lost over the past three months was gold XAU=, down 5.6 percent on the quarter and 9 percent on the year. That's largely because dollar strength and a vibrant U.S. economy have lured investors to the greenback instead of gold as a safe haven investment.

Also sharply down on the year are shares in European banks .SX7E which have also entered a technical bear market, pressured by concerns about Italian banks' sovereign bond portfolios and the sector's exposure to tumbling Turkish assets.