A sex riddle about bankers is:
 
Q: Why do men who are bankers make better lovers?
A: Because they know that there is a substantial penalty for early withdrawal.
 
The joke has been cited in print since at least 1993.
 
         
Google Books
Men and Other Reptiles
Chicago, IL: Contemporary Books
1993  
Pg. 97:
Question: Why do bankers make great lovers?
Answer: They know there’s a substantial penalty for early withdrawal.

Google Groups: rec.humor
Canonical List Of Sex Humor 2/7
^C^[Qq^Z^C^[^X^C^?^C^Z
6/9/94
(...)
Why do men who are bankers make better lovers?
Because they know that there is a substantial penalty for early withdrawal.
 
Google Groups: fido.ger.jokes
Maennerfeindliches
Klaus Grimme
3/5/97
(...)
Q. Did you know why bankers are good lovers?
A. They know the penalty for early withdrawal.
     
Google Groups: alt.jokes
1 up for the women
Little Frank
10/31/99
(...)
> Q.  Did you know why bankers are good lovers?
> A.  They know the penalty for early withdrawal.
 
Google Groups: alt.humor.puns
Adult Puns of the Weak 11-25-04
Stan Kegel
11/25/04
(...)
Do you know why bankers are good lovers?
They know first hand the penalty for early withdrawal. (Cathy)
 
3 February 2005, New Zealand Truth (Auckland, New Zealand), “The Porkbone Kid,” pg. 2:
BANKERS make the greatest lovers because they know the penalty for early withdrawal.
     
SadGeezers
Jokers: People Jokes: Dumb Bloke Jokes (Say That 3x Fast!)
Fri, 06/06/2008 - 16:57 |  SadGeezer
(...)
Do you know why bankers are good lovers?
They know the penalty for early withdrawal.
 
Twitter
Bitsy Blondell‏
@PinUpMom
Why do bankers make great lovers? B/c they know there’s a penalty for early w/drawl
1:46 PM - 22 Apr 2009
   
Google Books
The Best Jokes I’ve Heard, Volume 2
By Douglas Blankenship
Bloomington, IN: AuthorHouse
2011
Pg. 184:
Q: Do you know why bankers are good lovers?
A: They know first hand the penalty for early withdrawal.
   
Google Books
The Unofficial Joke Book of Malaysia
By Kuldeep Saluja
Diamond Pocket Books Pvt Ltd,
2015
Pg. ?:
Why. don’t bankers suffer from premature ejaculation?
Because they know there’s penalty for early withdrawal.
 
Twitter
lorraine Jo King‏
@LahLahBean
#Sidesplittingsunday Why do bankers make great lovers?
They know the penalty for early withdrawal. ☺
6:27 AM - 25 Feb 2018