LONDON - A leading emerging market stock index extended its slump since January to20 percent on Wednesday in a fresh wave of selling which took it into territory commonly regarded as a bear market.

The scale of the fall in MSCI's widely tracked 24-country emerging market index is likely to be painful for many investors, given the index compiler estimates that more than $1.9 trillion of assets globally are benchmarked to the measure.

The sharp drop in the index comes as the threat of a full-blown trade war between China and the United States has scuttled Chinese markets. Political stress has brought heavy losses in countries like Brazil, Turkey and Argentina, while a strong dollar - partly due to rising U.S. interest rates - has hit virtually anyone who borrows in the currency.

"It is dollar strength, Trump's trade wars and Fed tightening," said Renaissance Capital's global chief economist and head of macro-strategy Charles Robertson. "They are an ugly combination for emerging markets."

MSCI's latest data also shows the index has 830 stocks, with China making up 33 percent and other top countries like India, Brazil and Russia accounting for 9 percent, 6 percent and 4 percent respectively.

Charting the fortunes of individual countries shows just how broad-based the selloff has been. In hard cash terms it has wiped nearly $900 billion off the index's overall market capitalisation.

Turkish and Argentinian markets have both lost roughly 50 percent of their value in dollar terms, largely due to the collapse in their respective currencies.

Beyond those extremes however there are also nine other countries including heavyweights like Brazil, South Africa, Indonesia and China that have all dropped between 20 and 30 percent.

Further down the list, India is down almost 8 percent, Mexico 6.5 percent and Russia has slumped more than 15 percent despite sharp rises in prices of oil and gas, its largest exports.

That commodity price jump has left Saudi Arabia and Qatar as the some of the only emergingmarkets in positive territory.

In terms of the overall EM index, there is also now one of the most extreme divergences compared with MSCI's 47-country All Country world index on record.

The EM index has underperformed by just over 10 percent this year and by 45 percent over the last decade.

(Reporting by Marc Jones and Helen Reid; Editing by David Holmes)

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