The Economist has an article highlighting the various methods currency traders are using to evade controls placed on the yuan in China.

SINCE a police raid on her firm was broadcast on Chinese state television, To Ling has emerged as one of China’s more intriguing financiers. The 43-year-old Hong Kong resident operated a black-market foreign-exchange business with an outlet in Hong Kong, four branches on the mainland, and a client list that included China National Petroleum and Sinopec, two state-run monoliths. Her firm handled transactions worth more than $1m a day. Now she has landed in jail.

The crackdown on her operations in mid-November has exposed how hard it has become for the Chinese authorities to keep a tight rein on capital flows. Chinese citizens, with well honed trading instincts, have spotted a glaring arbitrage opportunity: subsidised petrol on one side of the border that Hong Kong residents want to get their hands upon, and cheap shares in Hong Kong, compared with their mainland counterparts, that Chinese investors want to buy. Officially, both are off limits to the other. That is where Ms To stepped in, providing the currencies both communities needed to do deals.