As its overseas assistance budget shrinks, Switzerland says it will rely more heavily on mobilising private capital to fund sustainable development in poorer countries. But the record on innovative mechanisms, such as “blended finance”, is mixed at best. In 2018, the site for Vietnam’s first industrial-sized solar power plant was 300 hectares of difficult-to-farm wasteland in the nation’s poorest province. Seven years later, with cash from Switzerland and a handful of other donors, the project is supplying enough power for 200,000 homes and cutting CO2 emissions by 240,000 tonnes a year. The project not only kickstarted a boom in solar production across Vietnam that has curbed dependence on coal. It was also remarkable for using about $20 million (CHF16 million) from donors as a lure to attract a further $147 million of investment from the private sector. Now, as development assistance from major state donors falls globally for the first time in years, Switzerland is among rich ...