From: Rabbi Moshe Sofer
To: Rabbi Sinai (Av Beis Din), Naftali, and Akiva
Orphans' funds given in an iska arrangement suffered losses due to an imperial devaluation of Austrian banknotes. The Chasam Sofer rules that the orphans must bear partial loss: on the deposit half of the iska the principle of harei shelcha lefanecha applies, so the devalued currency may be returned as-is, while the loan half remains owed in full. He rejects permitting fixed interest even for charitable or Talmud Torah funds, affirms that banknotes have full currency status, and holds that dina demalchusa dina governs debt repayment rates after government devaluation.
Source: Shu"t Chasam Sofer YD §134