Fair Market Value Of IRA Containing Short Options Contracts

[zx14rr]

Can anyone explain why Vanguard does not reduce the 12/31/XXXX fair market value (FMV) of a traditional IRA containing short option contracts by the amount which is required to "buy to close" the options contracts? While the annual end-of-year account statement reduces the FMV of the IRA by the "buy to close" amounts at 12/31, the IRA FMV calculation used by Vanguard to calculate the required minimum distribution does not thus resulting in a greater balance in the IRA account and an increased required minimum distribution. I have attempted to get an answer from Vanguard but have been unsuccessful. Thank you for any thoughts you may have.