Pension funds offer tax-deferred savings plans for working individuals to accumulate savings for retirement. There are two main types of pension funds - defined benefit plans where employers commit to providing a specific retirement benefit, and defined contribution plans where employers commit to specified contributions. Regulation of pension funds in the US is governed by ERISA which sets standards for funding, vesting periods, fiduciary responsibilities, and provides insurance for underfunded plans. Global pension systems vary, with some European countries having traditional state-funded pensions.