What a strange warning from Schwab when I tried to buy UUP puts: The underlying security of this option is currently considered Hard to Borrow. If this order results in a short position due to assignment or exercise, a borrow fee may be charged. The current estimated annualized borrow rate is 0.0 and estimated daily fee is $$0.00. Fees are subject to change based upon supply/demand in the market. Fees are not charged on covered strategies that result in net zero position if exercised or assigned. By placing this order you agree to pay this fee and that you have read and understood disclosures. Does anybody understand why they keep sending me these warnings?
If you're not long UUP then exercising the put would leave you short. Odd that the borrow is 0 but... it's a canned response triggered by a broad condition. The borrow rate info is merely convenience. Schwab can't pay programmers/engineers to write more conditionals and queries than economically necessary. They have to draw the line somewhere. If you don't understand the intention then you might want to reconsider the trade. If you do, then tick the checkbox that says "don't show this again"; provided there is one and you're sick of seeing it.