Imaginary barriers to communication which are set up voluntarily between two departments or sets of activities within the same company. The point of the exercise is to protect their clients’ rights to receive impartial advice, which might be compromised by privileged information being passed freely throughout the company. This applies, for example, to the market-making and brokerage functions of a stockbroking firm, where market-makers might be keen to sell a stock because they expected its value to fall, and the brokers then recommended the stock to clients. Numerous financial scandals in the 1980s and 1990s have shown that the walls are a lot more porous in practice than theory. Why the Chinese have been accorded such a dubious attribution is unclear.