“Any price that can be affected by the market must be left to the market?.?.?.” Hardly as snappy as Deng Xiaoping’s black or white cat. But, coming from the great Decision on China’s economic future, those words take the imagination far and wide. The Third Plenum, a top meeting of party brass, also promised to relax the one-child policy. Investors had best be cautious about Shanghai-listed Humanwell Healthcare. Its shares are 29 times forward earnings. It makes condoms.

The idea of market pricing implies a few more post-Plenum trades than the rather iffy one that has been popular so far – buying Hong Kong-listed consumer stocks. Maybe the China of 2020 justifies the multiples being paid: a future where, after unpacking the double stroller (Goodbaby, share price 20 times forward earnings) and the infant formula (Biostime, 32 times) from the SUV (Great Wall Motor, 14 times), families endlessly trot around up-and-coming cities. Or not, if fertility remains below replacement rates.

That leaves the two-thirds of profits on China’s stock market that will now be exposed to market forces. It is easy to imagine them falling. But whatever else 2020s China will look like, it will probably still need more and cleaner fuel, for example. If PetroChina and Sinopec can set higher retail prices, refining margins benefit. A $1 rise per barrel in margin at Sinopec would boost earnings per share next year by 10 per cent, Nomura says. Ecological promotion and higher pricing also aid PetroChina’s natural gas unit. This already returned to profitability on recent price increases.