SMAs are investment accounts managed by a professional money manager who creates a portfolio customized to the needs of individual investors. This custom tailored portfolio can be designed to meet specific needs or preferences of the individual, such as to exclude particular kinds of stocks (like vice or other social exclusions) or employer stock the investor may already own directly. They also allow the investor to design the portfolio according their own investment objectives.
SMAs offer the investor the benefits of professional management with additional customization. One of these is the additional tax management some SMAs allow on non-retirement accounts called tax harvesting. In some SMAs, managers can harvest gains and losses that are particularly selected to the investors situation.