> The primary purpose of CPF is not a pension scheme. It is structured as a massive forced bond purchase scheme by citizens. Financially what happens is the 37% of citizen income buys a long term bond (till retirement age, on average decades) at rock bottom interest rates (it's pegged to the overnight rate or a minimum of 2.6%).

Social Security is effectively the same thing. Payroll taxes are collected and placed in the social security trust fund, which invests them in federal bonds.