I want to hold Vanguard Total International Stock Index Fund in a Roth IRA and a taxable Vanguard account. Together they would total over $10k, but apart they would individually be under $10k. Both accounts are at Vanguard. I understand that Vanguard reviews your accounts annually and upgrades/downgrades to/from admiral shares depending on the amount held in a fund. Do they look at the total amount held by you as an individual, or do they look only at the amount held in each account?
Yes, each of Vanguard's mutual funds looks only at its own shares when deciding to upgrade/downgrade the shares to/from Admiral status. To the best of my knowledge, if you hold a fund in an IRA as well as a separate investment, the shares are not totaled in deciding whether or not the shares are accorded Admiral shares status; each account is considered separately. Also, for many funds, the minimum investment value is not $10K but is much larger (used to be $100K a long time ago, but recently the rules have been relaxed somewhat).