Carlyle, which went public last May, is doubling down on China, where it opened its first office 15 years ago. (KEITH BEDFORD/REUTERS)

The Carlyle Group completed its sale of China Pacific Insurance Group on Friday, a highly profitable deal that appears to run against the growing conventional wisdom that China may no longer be a vehicle for fat profits.

Carlyle, a Washington-based private equity group with a deep presence in China, earned nearly seven times its money on the life insurance company. The profits were partly driven by a rapidly growing Chinese middle class riding double-digit economic growth.

But that growth slowed by one-third last year, though it is registering a sizzling seven percent, raising concerns that profits in China will be harder to sustain. Many U.S. banks, for example, dove into China during the 2000s, only to see themselves stuck with useless investments.

Private equity firms such as Carlyle buy companies, restructure them to increase their value and then sell them with an eye toward a big profit.

“A slowing economy [in China] presents some particular opportunities,” said Kenneth Lieberthal, a China expert at the Brookings Institution. But private equity firms’ strategy is to hold onto their acquisitions until they see an especially profitable time to sell. If China’s growth is tepid, that lengthens the time necessary before Carlyle can flip the holding “and therefore reduces returns on investment.”

Despite observers’ concerns, Carlyle co-chief executive David M. Rubenstein said he was bullish on the firm’s China strategy. Even as that country’s economy slowed in 2012, Carlyle bucked the rising consensus, investing more than $700 million while selling more than $1.5 billion in companies.

“China grew at 10 percent for decades, so seven percent is still heroic,” said Rubenstein, who compared the current Chinese economic climate to the torrid growth that began in the United States in 1913. “Outside the U.S., China is still the greatest place to invest.”

William E. Conway Jr., a Carlyle co-founder and chairman of the firm’s investment committee, said last summer that he was keeping a close eye on China, although he still saw it as a place to invest.

China population’s is four times that of the United States, boosting demand for those middle-class goods and services, including appliances, infant formula, financial services and animal feed.

That kind of wealth has drawn interest from U.S. firms beyond the private equity sector, from McDonald’s to General Electric to Bank of America

Carlyle, which went public last May, is doubling down on China, where it opened its first office 15 years ago. During that period, Carlyle has invested nearly $5 billion in China through 70 transactions, according to the company. The firm has five offices in China, and one in 12 Carlyle employees is based there.

Howard Chen, a private equity analyst with Credit-Suisse, said Carlyle is better positioned to capi­tal­ize on China than most other competitors in the private equity field. The firm has spent a “tremendous amount of investment, resources and time” to establish its China beachhead, which could make Carlyle lots of money even in down times.

“Looking back, private equity returns are often highest in those vintages where money was invested during recessions or slower growth periods,” Chen said.