The world needs more money to achieve the 2030 sustainable development goals. Private money can help, but there's still a big gap. Middle-income countries can raise taxes to get more public money, but it won't be enough for low-income countries. Private money can also help, especially for building things like roads and schools. But there need to be good projects for investors to put their money into. Making better financial systems can help bring in more private money for important projects.