NEW YORK, Nov 10 (Reuters) - Investors should not ignore the long view for emerging market stocks even if many have latched on to surprisingly strong leaders in the asset class, Acadian Asset Management wrote in a paper published Tuesday.

Emerging market stocks as measured by MSCI have risen just under 6% in 2020, not far from the performance of the All-Country World Index. The U.S. benchmark S&P 500 has risen nearly 10% this year.

The EM performance has been very narrow geographically and only slightly less so sector-wise, with six of the top 10 members of the EM index based in China. The other slots are taken by Taiwan, South Korea, South Africa and India.

The top two index constituents, Alibaba Group Holding Ltd and Tencent Holdings Ltd are up 25% and 58% year to date.

"Quite often, we find that investors get more heavily weighted in terms of what has happened more recently, and less sort of what the longer-term patterns have been," said Ram Thirukkonda, senior investment strategist at Acadian.

That trend is evident in the EM index, where the overall index weight of the top 10 constituents at the end of October was 32.45%, a strong concentration given the index's nearly 1,400 components.

In the current context, "we see it as especially important for EM investors to recommit to strategies that provide exposure to a diverse set of returns drivers rather than chasing recent and narrow performance trends in the asset class," Acadian wrote, noting the "evergreen value of geographic diversification to long-term investors."

From a portfolio standpoint, however, investors have different time frames and Acadian is currently overweight South Korea, Taiwan and China in geographic terms and in technology, media and telecom services in terms of sectors, according to Kurt Livermore, a portfolio manager there.

Many long-term caveats remain in terms of EM performance including the effects of the COVID-19 pandemic, which has hurt some EM regions specially hard, like Latin America. But the crisis has a silver lining, as the rebound could also disproportionately benefit some in those markets.

"Any additional positive development, for example a vaccine coming out, or anything positive in terms of restoring economic growth, is going to be positive for EM," Thirukkonda said.

"When global economic growth returns post the pandemic they stand to benefit strongly." (Reporting by Rodrigo Campos; Editing by Richard Chang)