options-liquid sleeve where IMAX writes covered calls.
EFA is the more options-liquid sleeve in IMAX where covered calls are written, while IEFA is held passively.
EFA is described as having a more liquid options market than IEFA, enabling covered-call implementation. IMAX splits exposure so covered calls can be written on up to about half the fund on the EFA sleeve, targeting the yield level the strategy seeks.
"NEW Hamilton Covered Call ETFs: IMAX & CMAX | International Stocks + Income"