The only "large profits" that resulted from the sale of American DeForest Wireless stock actually went to the promoters selling the vastly overpriced securities. (The original scan of this advertisement is at: http://chroniclingamerica.loc.gov/lccn/sn83030214/1904-06-16/ed-1/seq-13/)
 
The New-York Tribune, June 16, 1904, page 13:
 
FOR  LARGE  PROFITS  BUY
American  De  Forest
W I R E L E S S
Russo-Japanese
War  News  Service.
    The  De  Forest  system  is  the  only  one  supplying  a  wire-
less  news  service  of  the  Russo-Japanese  War.  This  ser-
vice  is  daily  furnishing  the  latest  important events in  the
Far  East  to  the  leading  newspapers  of  the  world.
THE  7%  PREFERRED  STOCK
of  this  Company  affords  an  opportunity  for  investment
unqualified  in  fifty  years.  The  Company  has  now  in  hand
contracts  which  will  enable  it  to  much  more  than  pay  this
amount.
FOR    EVERY    $100   INVESTED
IT    WILL    RETURN   THOUSANDS.
Price  now,  $10.00  Per  Share.
WRITE  TO-DAY  for  full  information.
GREATER NEW YORK SECURITY CO.,
    91     WALL     ST.,NEW     YORK.