One reason could be to prepare them for a further widening of the yuan's trading limit, which some economists predict will be doubled this year to 2 percent either side of a daily midpoint set by the central bank.At the same time, forcing Chinese corporations to take on more currency risk implicitly makes invoicing and settling trade in yuan directly more attractive because doing so eliminates exposure to exchange rate risks. This advances another policy goal: increasing international use of the yuan in trade.