94 THE WORK OF THE STOCK EXCHANGE
to classes and kinds of securities and enterprises, and are modi-
fied from time to time as new conditions warrant. In formu-
lating them, the Committee on Stock List has had the benefit
not only of its own knowledge of securities and securities
markets, but also of the most expert advice in each case obtain-
able. Before composing its requirements for mining securities,
for example, the Committee consulted the Metallurgical So-
ciety, whose suggestions are embodied in the present form.
Similarly, in respect to the problem of listing petroleum securi-
ties, recourse was had to the American Institute of Mining
Engineers. More recently, the Committee after similar inves-
tigation established certain special listing requirements for
foreign government dollar bonds in 1925, for foreign internal
shares in 1927, and for investment trust securities in 1929.
All applicants for listing must comply with these require-
ments which tend to become more exacting year after year. It
must be remembered, however, that extensive corporate enter-
prise in many different industrial fields is still relatively new,
and hence, what should constitute proper listing requirements
for such securities has sometimes been a question to be decided
on little practical evidence.
Regulations Regarding Security Certificates.—Certain
requirements have to do with the form of the security cer-
rificates to be listed. They must be fully engraved and printed
from at least two steel plates in a manner satisfactory to the
Committee, and specified features of the issue must be clearly
set forth on their face. The Exchange also requires that the
work be done by an approved engraving company. When the
capital sums into which such security issues frequently run is
remembered, the need for the strictest measures to prevent
forgeries or overissues of certificates is apparent. The same
general problem with respect to American paper currency
forced the United States government to organize its Bureau
of Engraving and Printing.
By this strict supervision over the preparation of certificates
