“The bigger the party, the bigger the hangover” has been cited in print since at least 1962. However, the saying is now most often used in finance, referring to a hangover after an extended bull market. “‘The bigger the party, the bigger the hangover,’ says Mark Bickford-Smith, co-manager of T. Rowe Price New Asia fund” was cited in print in December 1995.
 
The word “longer” often replaces “bigger” in the financial phrase. “‘The longer the party, the bigger the hangover,’ he told his class, warning that a long bull market like the current one often precedes a big drop” was cited in print in October 1997.
 
 
Google Books
Canadian Saturday Night: A Magazine of Business & National Affairs
Volume 77
1962
Pg. 27:
And, of course, the bigger the party the bigger the hangover: fat tips are as likely to earn contempt as love; the most beautiful woman may be, like Zelda Scott, the lovely outward form of an inward desolation.
 
24 December 1995, Deseret News (Salt Lake City, UT), “Emerging market investors may be rewarded next year”:
“The bigger the party, the bigger the hangover,” says Mark Bickford-Smith, co-manager of T. Rowe Price New Asia fund.
 
19 October 1997, Augusta (GA) Chronicle, “Drop: Bull markets tend to last longer,” pg. 3F, col. 6:
“The longer the party, the bigger the hangover,” he told his class, warning that a long bull market like the current one often precedes a big drop.
   
Google Books
The Complete Idiot’s Guide to Italian History and Culture
By Gabrielle Ann Euvino
Indianapolis, IN: Alpha Books
2002
Pg. 191:
The bigger the party, the bigger the hangover, and the headaches Italy faced after unification were painful indeed.
   
CNNMoney
Market corrections
Why has the Nasdaq fallen so much more than the Dow?
October 9, 2002: 12:04 PM EDT
By Walter Updegrave, CNN/Money Contributing Columnist
(...)
Which means that when investors finally stepped back and realized what they were paying for stocks in the Nasdaq and Dow, the Nasdaq shares got punished a lot more, the stock market’s version of the “harder the party, the bigger the hangover” theory.
 
The Market Oracle
Stocks Bull Markets Climb a Wall of Fear
Nov 16, 2007 - 12:32 AM GMT
By: Regent_Markets
After the party comes the hangover, and of course the bigger the party, the bigger the hangover.
     
Zero Hedge
Guest Post: The Brewing Generational Conflict
Submitted by Tyler Durden on 05/15/2013 14:27 -0400
(...)
COMMENTS
AlaricBalth
Wed, 05/15/2013 - 14:54 | 3565820
(...)
You know the old saying; the longer the party the bigger the hangover. Well, this hangover may last 25-30 years until the last of my generation are dead, either through natural causes, death panels or intergenerational warfare.