First Boston was a New York City-based investment bank, founded in 1932. First Boston was acquired by Credit Suisse in 1990; First Boston was called “CS First Boston” from 1993 until 2006.
 
The First Boston nickname of “Worst Boston” was used since at least 2002 and 2004.
 
     
Wikipedia: First Boston
First Boston Corporation was a New York-based, bulge bracket, investment bank, founded in 1932 and acquired by Credit Suisse in 1990. Together with its sister investment banks, it was referred to as CS First Boston after 1993 and part of Credit Suisse First Boston after 1996, the First Boston part of the name was phased out by 2006.
 
TheStreet
The Five Dumbest Things on Wall Street This Week
By George Mannes   10/25/02 - 07:10 AM EDT
(...)
Runaway growth at HSBC; Applied Digital’s chip of fools; confidence game at DGIT; idol dreams on Wall Street; First Boston or Worst Boston? 07:10AM 10/25/02
 
Google Books
Running Money:
Hedge Fund Honchos, Monster Markets and My Hunt for the Big Score
By Andy Kessler
New York, NY: HarperBusiness
2004
Pg. 59:
“That guy probably called into Moron Stanley or Worst Boston and shorted Micron’s stock, and then told them he heard straight from their investor relations that things are a disaster, PC makers have stopped buying, prices are collapsing, the fab is on fire. who knows.”
Pg. 208:
Less than a year after meeting with Mr.Shinn of Ssangyong, CS First Boston (or Worst Boston, as Nick Moore would probably say) took our little chip company public at $18.