It seems like every broker has wording saying it is not officially approved and its up to YOU to take the risk of losing tax free status should the IRS issue a negative directive on them.
your broker. it is not real margin that you can borrow against or leverage up. it is letting you to access unsettled funds realtime.
“ requirements To be approved for limited margin at Fidelity, the investment objective on your IRA must be "most aggressive." At Fidelity limited margin will also add the pattern day trader designation, so you must also maintain minimum equity of $25,000 or more within your account. Some brokerage firms, including Fidelity, have additional requirements. For example, at Fidelity you cannot select an FDIC-insured vehicle as your core account option within your account. Other restrictions may apply, so be sure to check the eligibility requirements on your broker dealer’s website. Once your IRA is approved for limited margin, trades in your account will default to the margin account type to fully utilize this feature. However, you will need to contact a representative to transfer your current positions to margin. If you intend to trade stocks or options actively, you should refer to your intraday buying power balance. This balance updates throughout the trading day to reflect trade executions, money movement into and out of the account, core cash, and buying power allocated to open orders. See Viewing margin trading balancesOpens in a new window for more information.” Fidelity