Shares of Singapore-listed membrane products maker Memstar Technology (MEMS.SI) rose as much as 14.3% on Tuesday on increased investor interest in China-related and clean technology stocks.

Over 10 million shares had changed hands by 10:27 a.m., and the price was up at 7.5 cents.

“There has been a rotational play on environmentally-related penny stocks, especially those with business in China,” a trader at a local brokerage said.

In May, Memstar reported a 297% increase in its third quarter net profit to 7.7 million yuan ($1.5 million) mainly due to increased sales to the Guangzhou Municipal Government for its wastewater treatment plant.

Shares of Singapore-listed water treatment firm United Envirotech (UNIT.SI) rose as much as 7.8% to a nine-month high of $0.415 last week on expectations it may expand operations in China.