"Bulge bracket" is a slang term used to describe the largest underwriting companies in the industry. They are the group of investment banks considered to be the world's largest and most profitable. Because there are no precise criteria for inclusion, there is sometimes debate over which banks belong to the bulge bracket. Various rankings are often cited, such as Thomson Reuters League Tables or other league tables.
The bulge bracket is usually the first underwriting bank or banks listed on the tombstone, which is an advertisement of a new issue. The font size of the name of this bank or banks is larger and it may "bulge" out.
Syndicates are formed in the investment banking industry so underwriting companies can share the risks and profits associated with a new security issue with other firms. The larger the new security issue, the more firms are likely to take part in it through syndication; however one firm is likely to act as the manager or co-manager of the syndicate.
Before the subprime mortgage crisis of 2007-2008, the five American Bulge Bracket firms on Wall Street were, from largest to smallest: Goldman Sachs, Merrill Lynch, Morgan Stanley, Lehman Brothers, and Bear Stearns.