I asked TD Ameritrade about GTC orders stopping your shares from being lent for shorting
NO, it will not stop the brokerage from lending out your shares for shorting as long as you have margin account even if you have so much cash and you have not bought anything on margin, like I am. I have three accounts, cash, 401K and simple IRA. Of course, my 20k nok shares in my 401K and simple IRA account can't be lent for shorting, but my 10k shares in my cash account which is margin can be lent for shorting regardless of whether I put a GTC order or not. I am letting you, cause I read all the time about people advising others to put their shares on GTC (good till cancel) orders. At least that is what a lady broker told me at TD Ameritrade. Call your other brokerages to verify this.
Close the margin feature but keep the cash account should do the trick. So long as you have the NOK shares in the margin account, you're allowing the firm to hypothecate your shares.
If you had read the margin account before signing it, you would have caught that.
I don't care, cause it is not an issue for me. The reason I am noting is there are people who believe GTC will stop shorting and it won't as long as your cash account is on margin. There is a reason why you need to have a margin account and if you have read about margin accounts, you will know the benefit of having it instead of closing the margin featuret. Why close the margin feature?? It does not make sense, cause it gives you a lot of leverage in the way you trade regardless of how much cash you have in your account. I know. I have a lot of cash and still keep the margin feature as I find it very beneficial.