Mizuho Financial Group Inc. will start artificial-intelligence trading to bolster its Japanese equity business, according to people with knowledge of the plan.

Japan's third-biggest lender will begin offering an algorithm-based AI trading service to some large institutional clients in Japan and elsewhere in Asia, the people said, asking not to be identified because the plan is private. The product attempts to predict how stock prices in Japan will change over an hour and find the best time to trade, they said.

Global banks are seeking to improve the quality of their trading execution and equity research before the European Union's revision of the Markets in Financial Instruments Directive, or MiFID II, comes into force in January. Under the new rules, brokerages will be required to separate research fees from trading commissions to ensure investors pay fair prices for the services, a move that may spur competition.