Brutality scorecard: Which emerging stocks have it the worst?

Kunal Patil | Hindustan Times | Getty Images

There's been no let-up in the 'taper tantrum' that has demolished stocks across the emerging markets in recent months, a trend that could continue as investors turn cold on an asset class that was a market favorite until about six months ago.

Emerging market stock indexes have registered severe, in some cases double-digit, losses since the U.S. Federal Reserve first began talking about scaling back its extraordinary monetary stimulus in late May.

Indonesia's benchmark Jakarta Composite Index - the biggest loser among emerging markets - has plunged over 20 percent in the past three months, putting it in bear market territory.

Neighboring Southeast Asian markets including Thailand and the Philippines are not far behind, with losses amounting to 17 and 11 percent, respectively, over the same period. India's Bombay Sensex, meantime, has declined more than 10 percent.

(Read more: Activity in BRICs shrinks for first time in 4 years)

Experts say the selling represents an important transition in markets: a shift back to fundamentals.

"The big change in market perception is that six months ago or a year ago, investors were praising the economic management in EM [emerging markets], comparing it favorably with G10. Now they are looking at these countries and saying wait a second, we are seeing weaknesses that we had overlooked," said Steve Englander, global head of FX strategy at Citi told CNBC on Tuesday.

"And those weaknesses are much more important that we have been thinking in the last 10 years," he said.

While the selling across emerging markets may appear indiscriminate, experts say it's not.

"If there's a redeeming feature to the current sell-off, it's that investors are the most concerned about the emerging markets that are the most concerning. Unfortunately it took a sudden rise in U.S. interest rates to force investors to pay more attention to country-specific risk," said Nicholas Spiro, managing director at Spiro Sovereign Strategy."

(Read more: Is this the only way out of EM's rut?)

"Emerging Asia is perceived as the most vulnerable region - and India and Indonesia are the focal points for market anxiety. While other emerging markets, notably Turkey and Brazil, remain out of favor with investors, sentiment towards India and, to a lesser extent, Indonesia is unremittingly bleak," he added.

Brazil's Bovespa stock index has declined around 8 percent since late May, while Turkey's ISE National-100 index has decline almost 21 percent - driven largely by political unrest in the country.

(Read more: Turkish stocks drop 10.5% on fourth day of protests)

According to Nicholas Ferres, investment director of Global Asset Allocation at Eastspring Investments, India and Indonesia have had it the worst, and for good reason.

"The price action in the two markets of India and Indonesia smacks of panic. In many respects this is warranted given the inability of policy makers to stabilize the respective currencies," he said. "Similar to the risk in India, Indonesia's equity valuation does not offer a margin of safety for these risks."

Investors can expect more pain for the asset class in the coming weeks, as U.S. Treasury yields continue to rise, said Mark Matthews, head of research Asia at Julius Baer.

(Read more: Multimillion-dollar bet against emerging markets)

"The Treasury bill is perceived as the least risky asset in the world, and emerging markets are perceived as very risky assets. If you get more return in the least risky asset, then the most risky assets will be less attractive, and that's the balance that's been shifting," he said.

—By CNBC's Ansuya Harjani; Follow her on Twitter @Ansuya_H