be insiders in the firm who own a significant portion of the equity of the firm and are
involved in the management of the firm.
While it is difficult to identify the marginal investor in a firm, we would begin by
breaking down the percent of the firm’s stock held by individuals, institutions and
insiders in the firm. This information, which is available widely for US stocks, can then
be analyzed to yield the following conclusions:
• If the firm has relatively small institutional holdings but substantial holdings by
wealthy individual investors, the marginal investor is an individual investor with a
significant equity holding in the firm. In this case, we have to consider how
diversified that individual investor’s portfolio is to assess project risk. If the
individual investor is not diversified, this firm may have to be treated like a
private firm, and the cost of equity has to include a premium for all risk, rather
than just non-diversifiable risk. If on the other hand, the individual investor is a
wealthy individual with significant stakes in a large number of firms, a large
portion of the risk may be diversifiable.
• If the firm has small institutional holdings and small insider holdings, its stock is
held by large numbers of individual investors with small equity holdings. In this
case, the marginal investor is an individual investor, with a portfolio that may be
only partially diversified. For instance, phone and utility stocks in the United
States, at least until recently, had holdings dispersed among thousands of
individual investors, who held the stocks for their high dividends. This preference
for dividends meant, however, that these investors diversified across only those
sectors where firms paid high dividends.
• If the firm has significant institutional holdings and small insider holdings, the
marginal investor is almost always a diversified, institutional investor. In fact, we
can learn more about what kind of institutional investor holds stock by examining
the top 15 or 20 largest stockholders in the firms, and then categorizing them by
tax status (mutual funds versus pension funds), investment objective (growth or
value) and globalization (domestic versus international).
• If the firm has significant institutional holdings and large insider holdings, the
choice for marginal investor becomes a little more complicated. Often, in these