MSCI Inc. dropped plans to add a high-flying Hong Kong stock to its suite of indexes, a rare reversal after some market participants expressed concerns about the company’s investability.

ArtGo Holdings Ltd., which had soared almost 3,800 percent this year for the world’s biggest gain among companies with a market capitalization of at least US$1 billion, plunged 97.94 percent Thursday as traders reacted to MSCI’s decision.

The U.S. index compiler, which announced its intention to include ArtGo just two weeks ago, said in a statement Wednesday that it would no longer do so after “further analysis and feedback from market participants on investability.”

An ArtGo representative said the company, a marble producer that has been expanding into other businesses like real estate, couldn’t immediately comment.

ArtGo’s rally had flummoxed market veterans in Hong Kong, with prominent activist investor David Webb warning readers of his namesake website in September that the stock was a “bubble.” Its surge was the latest in a long list of extreme, unexplained swings on the Hong Kong exchange that have prompted some investors to urge MSCI and other index compilers to tweak their screening criteria to weed out such stocks.

MSCI was criticized earlier this year for including Hong Kong-listed China Ding Yi Feng Holdings Ltd. in its indexes after the company rallied 8,500 percent in five years despite repeatedly reporting operating losses. The stock was later suspended by Hong Kong’s securities regulator. (SD-Agencies)