Rakuten Securities to Auto-Invest Idle Cash via MRF from Sep 20

From Sep 20, Rakuten Securities will auto-sweep idle cash — proceeds sitting in your account after selling stocks or funds — into a money reserve fund (MRF) to earn yield, auto-redeeming it when you buy stocks. For Taiwanese buying Japanese equities or eyeing a Japanese brokerage account, it's a handy tool. The key is 'waiting cash': investors often hold sale proceeds not yet redeployed, earning nothing. Sweeping it into a money fund lets idle cash earn a little in the gap, with auto-redemption so it doesn't interrupt trading — and that bites more as rates rise and the opportunity cost of cash climbs. The signal: Japanese brokerages are competing on 'even your cash earns' amid rate hikes; if you hold Japanese stocks, check whether your broker offers similar cash sweeps. Watch whether rival brokerages follow — once idle-cash yield becomes standard, it's a contest of rates and experience.