When China's new breed of super-rich speak of their liquid assets, they may have something unexpected in mind.
Wealthy businessmen in Hong Kong are proving themselves the fat cats who've got the cream as a new craze for wet-nurses takes hold among the moneyed classes.
Young mothers from poor rural areas are being recruited by an agency over the internal border in Shenzhen in southern Guangdong province to produce breast milk for rich buyers convinced of its holistic benefits.
"Breast milk is the best tonic, especially for those people who have just undergone major surgery," said Lin Jun, the manager of the Xinxinyu Household Service Company, a domestic help agency.
Lin said his "adult nanny" clients included wealthy couples from Hong Kong and overworked company directors. Attractive nurses and those in good health command the highest prices, he added.
"If it is required, the customers may feed directly from the young mothers' breasts. But they can always drink it from a breast pump if they feel uncomfortable," he told the Southern Metropolis Daily.
Lactating mothers are hired by wealthy families for six to eight months and can earn up to 16,000 yuan (£1,700) a month, vastly more than a factory job pays.
Demand for the product rose sharply after a scare over tainted baby formula milk, which left six infants dead in 2008.
But while so-called "adult nannying" affords rural women the chance to earn huge sums in a short time, China's one-child policy means they would only be able to carry out the work once.
One 25-year-old mother said she chose to sell her milk rather than give it to her baby son in order to supplement her husband's 2,000 yuan-a-month pay packet and help pay for her child's education.
The report sparked intense debate on Chinese social media, with many commentators branding the trade unethical.
"This adds to China's problem of treating women as consumer goods, and the moral degradation of China's rich," said Cao Baoyin, a writer.
Xinxinyu's operations have now been suspended and its business licence revoked over unrelated administrative failures, regulators in Shenzhen said.
Wet-nurses hold an important place in Chinese tradition. Pu Yi, the last emperor of China, was suckled into his teens but the practice was banned as decadent by Chairman Mao.
Li Haifeng, an associate professor at Shanghai University of Traditional Chinese Medicine, said: "Breast milk can nourish the internal organs and it is noted that old people can drink it to prolong their life."
Mainstream medical opinion on the subject is at odds with the practices of traditional Chinese medicine, however. Human milk could cause stomach ailments and spread disease, said Gu Zhongyi, a nutritionist at Beijing Friendship Hospital.
"Breast milk has globulin to help improve babies' immunity, but adults do not need to build their immunity," said Gu. "It is not a good choice for adults."