Turkey ETF set for worst day in over three years after Erdogan's main rival detained

** Exchange-traded funds focused on Turkey tumble, tracking selloff in domestic markets

** U.S.-listed iShares MSCI Turkey ETF TUR drops 11.7% to $33.37, hitting more than four-month low and heading for worst session since December 2021

** Turkish authorities detain Ekrem Imamoglu, President Tayyip Erdogan's main political rival

** Main opposition party calls move "a coup against our next president"

** Paris listing of Amundi MSCI Turkey UCITS ETF TUR down 12.1% at lowest level since November, also set for worst day since December 2021

** Turkish lira USDTRY hits new record low against U.S. dollar; BIST 100 index XU100 drops 8.6% and set for worst day since February 2023

** TUR ETF trading at more than 12% discount to net asset value - data compiled by LSEG

** With day's losses, TUR has turned negative for the year, now down 7% YTD