This is probably a good question with which to begin.

According to Webster's, an activist is a person that has

a doctrine or practice that emphasizes direct vigorous action especially in support of or opposition to one side of a controversial issue.

It seems to me that as concerns investing, the "direct vigorous action" part of the definition applies more than the "one side" part. After all, investors that call themselves activists act directly to influence management, and do so vigorously through legal, public relations, and other means.

We also need to distinguish activists from active investors. The latter moves in and out of investments frequently, based on strategy, news, or whim. They contrast with passive investors, who buy and hold investments for a longer period of time.

An activist can be either active or passive, and probably fits the passive investor profile better. They buy and hold an investment, usually because taking an activist approach requires time and patience as an activist's ideas take hold.

So, an activist takes direct vigorous action to influence management of the companies in which they invest. Some activists start out that way, and others find themselves needing to become one. By this I mean some investors seek out investments, usually underperforming companies, that the investor thinks will improve with direct vigorous action to influence firm management's decisions.

Many don't start out that way, though. An investor takes a stake in a company that they like, and intends only to hold the shares. At some point the company's fortunes decline. For one reason or another, the investor cannot or will not sell at a loss. So, rather than sell at a loss, the investor takes direct, vigorous action, again to influence firm management's decisions.

Most inadvertent or unintentional activists care only about the value of their investment. They have no other agenda than recovering losses, or helping a firm improve financial performance.

Deliberate activists come in many flavors. Some work just like inadvertent activists, spotting money-losing companies that they think will turn around if management takes the investor's advice about how to improve the business.

Others urge changes in governance, in all of its detail and glory, including how the company elects directors, how those directors operate, how the company deals with buyout offers, or how the company pays its executives, among other ways that a company governs itself. These investors believe that changes in governance lead directly and materially to improvements in profits.

Still others want companies to adopt a range of policies and programs that promote a variety of parochial goals not necessarily related directly to earning profits. These goals include how a company treats the ecology, livestock, workers in third-world countries, customers in inner-city neighborhoods, national and local politicians, or friends and relatives of senior executives. These investors usually take direct, vigorous action because it help to publicize their cause.

This forum is for all activist investors, deliberate and inadvertant, with whatever motive for taking direct, vigorous action concerning their investments. I'm most interested in activist investors that want to make money, altough others have something useful to add to the discussion.