An investment strategy where individual investors choose to build and manage their own investment portfolios. Do-it-yourself (DIY) investors commonly build and manage their portfolios with the use of discount brokerages, as opposed to full-service brokerages or money managers. It is common to find a sharp rise in the level of DIY investing following market downturns or economic uncertainty.

The advent of discount brokerages and a multitude of online investment tools has led to a large increase in DIY investing in recent years. Individual investors will often choose to manage their own investments and leave their brokerages, portfolio managers and mutual funds due to the management fees associated with those investments, or the poor performance of their investments relative to the broader market. Although discount brokerages do not charge management fees, they still charge trading and maintenance fees which can eat away at an individual investor's portfolio.