Weird usage of these words... I know it's more frequently used as "Maple LeaFS" and "treasurYS"... but it just bothers reading. I still think it's more correct to say "Maple Leaves" and "treasuries". :| What is your opinion?
Maple Leaf is the compound noun and so Maple Leafs is the plural. Treasury Notes/Bonds (etc) is the compound noun so theory would say the abbreviation 'Treasury' would be 'Treasurys' as plural but I've always seen it shown as 'Treasuries' - which appears to be correct if spelling rules are applied. In fact one should probably use the second part of the compound noun (e.g. 'bonds') when the first part has multiple interpretations. I think.
'Treasuries' implies you're trading in physical treasury buildings, to me. 'Treasurys' is really an abbreviation of Treasury Bond as pointed out so is grammatically awkward but more preferable to me as a plural of an abbreviation. Don't know if I'm making sense?