By Georgina Lee

HONG KONG The 24 companies that debuted the yuan-denominated stock trading scheme in Hong Kong attracted a small fraction of their stocks' trading volume on Monday, as interest in using the new currency option was dwarfed by the Hong Kong dollar.

Hong Kong Exchanges & Clearing began the so-called HKD/RMB dual share counter trading across two dozen firms on Monday allowing investors the option to trade stocks across the two currencies. The scheme represents part of the city's effort to bolster its role as China's offshore yuan hub and speed up the currency's international use.

The top-three yuan counters that were most actively traded in terms of number of shares traded were CNOOC, which rose 1.4% to 10.38 yuan; China Mobile, which rose 1.9% to 59 yuan; and Geely Auto, up 0.6% at 9.1 yuan.

The three stocks bucked the downward trend of the Hang Seng Index, which slipped 0.6% to finish at 19,912.89.

A total of HK$177 million ($22.65 million) worth of yuan shares were traded on Monday, according to the HKEX, compared to HK$29 billion ($3.71 billion) traded across their Hong Kong-dollar counters.

For now, the dual counter service allows investors in Hong Kong to trade stocks using the 833 billion yuan offshore yuan pool in Hong Kong.

But the HKEX is working with Chinese regulators to allow mainland investors to eventually participate via the Stock Connect investment channel that connects the Hong Kong, Shanghai, and Shenzhen stock exchanges.

That could channel more trading volume into the Hong Kong bourse, as mainland investors currently trading Hong Kong stocks through the southbound leg of the Stock Connect face an exchange rate risk between the two currencies.

The Hong Kong dollar counter will remain the most traded currency for the southbound Stock Connect even after the yuan-counter is introduced, said Frank Shao, deputy head of equity investment at CSOP Asset Management.

Still, "many of our investors... are considering making the switch to the yuan-counter due to the elimination of exchange rate risk," said Shao.

($1 = 7.1601 Chinese yuan renminbi)

($1 = 7.8160 Hong Kong dollars)

($1 = 7.8171 Hong Kong dollars)

(Reporting by Georgina Lee; Editing by Shailesh Kuber)