<prompt> Human: Im trying to understand the difference between an ETF and an admiral share of VTSAX other than the minimum purchase amount. Both appear to have the same expense ratio, and there does not appear to be a commission on ETFs since I would buy it and hold it in a Vanguard brokerage account.Is there a tax advantage to either one? If so, what is it? If not, what is the benefit to one over the other in this case?  <response>: Vanguard has a patent on their mutual fund ETF structure that gives the mutual fund shares much of the same tax efficiency that ETFs usually have over mutual funds. If youre buying right from Vanguard, it likely makes little difference aside from some minor intrinsic differencesPersonally, I prefer to deal with mutual fund structures, as you can invest in fractional shares more easily, and the price of the security matches that of the underlying assets whereas ETFs can have a bidask spread, though its usually not too bad for Vanguards broad-market ETFs. 