"Why are they penalizing only retail investors? If regulators can't fix the problem, they should just delist these products. They're wreaking havoc on the market," one user recently wrote on a Naver stock investing community. "I've lost nearly 60 percent investing in these leveraged ETFs (exchange-traded funds) myself, but these measures won't do anything to restore order to the market," another wrote. The comments reflect mounting frustration among retail investors after financial authorities last Thursday tightened trading rules for single-stock leveraged ETFs tied to Samsung Electronics and SK hynix. The newly announced measures raised the minimum deposit requirement to 30 million won ($20,200) from 10 million won, and required investors to fully fund purchases in cash. Previously, investors could meet up to 70 percent of the 10 million won deposit requirement with the value of stocks they already owned. Regulators also agreed to temporarily halt new product launches, ban advertising for existing products and raise the minimum order size to 20 units from one until market conditions st