From Traderpedia

A pension fund is a portfolio comprising money and investments intended to provide retirement funds to a group of people.

Pension funds were once ubiquitous. Most major employers and governments had them to provide the pension payouts of their retirees. Many still exist, often in a legacy role. With the advent of defined contribution retirement plans such as Individual Retirement Accounts (IRAs), 401k programs, and others, the pension fund in its traditional sense related to defined payment plans has taken a backseat.