The Tokyo Stock Exchange will limit the size of individual stock purchase orders to less than 30 percent of a company's outstanding shares by the end of April, Liberal Democratic Party and TSE sources said Friday.
The TSE is taking the action to stem large, erroneous brokerage orders, they said. It will also publicly identify, beginning in May, any brokerage that places a botched order over a certain size.
TSE representatives presented the plan at a meeting of lawmakers from the ruling LDP's panel on financial system affairs.
The bourse will modify its computer trading systems to incorporate the limit, the sources said.
The plan to set the purchase ceiling was devised in response to a mistaken order last December by Mizuho Securities Co. to sell 610,000 shares in a newly listed staffing firm, J-Com Co., for 1 yen each, instead of one J-Com share for 610,000 yen.
The order set off a stampede by brokers and individual investors to cash in on the suddenly bargain-priced stock.
The TSE will also verify with brokers the accuracy of orders in excess 5 percent of a firm's outstanding shares, up to the 30 percent limit, the sources said.
The exchange will suspend orders found to be in error and urge brokerages to cancel them.
The TSE will also consider a proposal made at the meeting by an LDP lawmaker to identify all brokerages that place erroneous securities orders, regardless of the size of the purchase.