Chinese mainland shares in Hong Kong extended the biggest sell-off in Asia this year on concern the nation's deepening economic slowdown will sap corporate earnings.

The Hang Seng China Enterprises Index slid 1.3 percent at the close, completing a third day of losses. China Life Insurance Co and GF Securities Co led declines by financial stocks. The Shanghai Composite Index closed 0.3 percent higher.

The Hang Seng China gauge has decoupled from mainland equities this year for the first time in a decade as the government intervened to support shares in Shanghai and Shenzhen and foreign investors turned bearish on the nation's earnings prospects. While the index of mainland stocks in Hong Kong has fallen 19 percent in 2015, the most among Asian benchmark indexes tracked by Bloomberg, the Shanghai Composite Index has climbed 10 percent.

"The mainland market is likely to remain volatile in the first half as growth will slow further and the yuan is expected to weaken," said William Wong, head of sales trading at Shenwan Hongyuan Group Co in Hong Kong. "H shares are vulnerable as more United States rate hikes will affect the economy in Hong Kong as well as market sentiment."

Investors have been driven away from mainland shares in Hong Kong by weak economic growth, surging volatility in mainland equities and an anti-graft campaign that led to the disappearance or arrest of some of the nation's most high-profile corporate executives. A weaker yuan also cuts the value of corporate earnings by H shares, which are priced in Hong Kong dollars.

The Hang Seng gauge trades at 7.2 times reported earnings, the biggest discount to the MSCI All-Country World Index since 2003.

The CSI 300 index rose 0.1 percent as telecom and technology companies advanced, offsetting losses in financial and utilities stocks. ZTE Corp rallied 1.9 percent, rising for a second day, while SDIC Power Holdings Co slid 1.2 percent.

While H shares extend an annual tumble, a degree of normalcy has returned to mainland equity markets. A gauge of 50-day price swings has fallen to the lowest level in seven months, while the Shanghai Composite is poised for the best performance among major global indexes this quarter. Regulators have removed some support measures implemented at the height of a $5 trillion rout, while a ban on selling by major shareholders is due to expire next week.