In American English, bills, notes, bonds, and securities issued by the United States Department of the Treasury are Treasurys. The word has an initial capital letter, and it is pluralized in an unorthodox way—with -ys instead of the conventional -ies. We can’t explain why Treasurys is pluralized this way, and the theories we’ve heard are unconvincing. What matters is that this is how it’s done by people and publications with clout in finance and economics. Treasurys is ungrammatical, but we can’t pretend people don’t use it.
Examples
Treasurys is preferred by financial writers—for example:
And our foreign lenders might abandon Treasurys for a safer security. [Forbes]
The prospect of trouble in the all-important market for Treasurys is only adding to their worries. [Washington Post]
Private foreign investors sold a record amount of U.S. Treasurys in June as the U.S. debt-ceiling debate intensified … [Wall Street Journal]
Elsewhere, Treasuries (sometimes just treasuries) often appears in reference to U.S. Treasurys—for example:
For generations, the United States and its debt—sold in the form of U.S. Treasuries—have been synonymous with safety. [NPR]
One way to judge how worried the market is about Washington’s poisonous politics is to look at the cost of insuring U.S. Treasuries. [The Atlantic]
In a key indicator of demand, prices of 10-year U.S. Treasuries have risen for three straight days after the S&P downgrade late Friday. [Los Angeles Times]
And of course, for all treasuries not issued by the U.S. Department of the Treasury, treasuries is correct.
