flattener

English

Etymology

From flatten +‎ -er.

Noun

flattener (plural flatteners)

1. Anything that flattens.
2. (finance) A trade whose terms are based on the assumption that the rate of return will decrease.
   • 2012, Howard Corb, Interest Rate Swaps and Other Derivatives, page 451:

     Provided that the curve doesn't ever flatten too much and the option remains out-of-the-money, then we will put on flatteners when the curve steepens and put on steepeners when the curve flattens.

   • 2014, Greg Gliner, Global Macro Trading: Profiting in a New World Economy:

     For example, if a trader thought that 2's 10's would trade lower than 185, he or she would put on a flattener.