Yumiko Okubo, 71, had forgotten how to heat up food. “What’s a microwave?” she asked her husband, Eiichi. Yumiko was in the early stages of dementia, struggling with vocabulary and unable to teach the kimono-dressing classes she had run for 25 years. The difficulty with everyday tasks has made life challenging for her and Eiichi, who has been caring for her since 2008. But she is also unable to deal with her finances - a situation that experts say is increasingly common in fast-ageing Japan and that puts trillions of yen worth of assets at risk. Rika Kambayashi, a social worker in Kyoto, says she has seen many cases of dementia patients withdrawing large sums without a clear grasp of what they are doing or why. In one example, she said, a woman in her 90s withdrew 20 million yen ($266,000) of her savings at a grandson’s urging. “She was saying she withdrew nine or ten. It took me a while to realize she was talking about a number of banknote rolls. A roll is typically one hundred 10,000 yen notes. It was clearly a case of abuse," Kambayashi said. According to Reuters, dementia has been diagnosed in more than 5 million Japanese. The government estimates that number will increase to 7 million to 8 million, or 6 to 7% of the total population, by 2030. The Organization for Economic Co-operation and Development (OECD) has a somewhat lower estimate that dementia will affect 3.8% of Japan’s population by 2037, still the highest among the 35 OECD states and far above the average of 2.3% predicted for the group. Japanese with dementia will hold about 215 trillion yen ($2 trillion) in financial assets by 2030, compared with 143 trillion yen now, according to estimates by Dai-ichi Life Research. Jin Narumoto, professor of psychiatry at Kyoto Prefectural University of Medicine, said that many companies now face risks in doing business with people with dementia, whose families may return later to ask that the transaction be canceled. A survey by Narumoto and three other researchers found about 30% of dementia patients and families have experienced financial losses because of the condition. Bank officials say tellers now regularly encounter people with dementia who cannot use an ATM or who repeatedly ask the same questions. Some behave strangely, accuse employees of theft or even become violent. By 2030, about 31% of Japan’s population is projected to be 65 or older. As the country’s life expectancy is 84 years, the highest in the world, the problem of dementia will only intensify. Dementia is caused by several diseases, with Alzheimer’s accounting for about two-thirds. It covers a range of symptoms, broadly defined as a decline in memory and thinking serious enough to hamper daily life. As banks encounter more customers dealing with dementia, many, such as Nomura and Sumitomo Mitsui Trust Bank, are educating staff about how to safely and fairly handle interactions. In Tokyo, five cooperative financial institutions jointly set up a non-profit association to offer low-cost financial guardian services for people with dementia, working closely with a local government. Guardians are appointed by a local court and help their clients professionally manage finances. They can act on behalf of their clients and even cancel contracts or purchases if needed. But such systems have been prone to abuse. From 2010-2015, there were almost 3,000 reported cases of misuse, with 21 billion yen stolen by guardians, and many experts say there is little oversight.