the distinction between cost method and lot selectionExactly. Further, each - cost basis and lot selection - is a distinct legal (accounting) fiction. In reality shares owned are nothing but fungible writings in an electronic ledger.
For the tax purpose of computing gain, the IRS offers two different methods of ascribing cost - average and actual. If there is no gain to be calculated for taxes (as is the case for tax-sheltered accounts), then there is no cost basis.
That doesn't preclude investors from thinking about how much money they made in buying and selling shares, regardless of whether they are taxed on cap gains. To facilitate this, brokerages often provide their own tax-sheltered "cost basis" calculations for investors to track gains in their minds. Though not on their
1040s.
To illustrate this dichotomy between tax purposes and investor perceptions, consider income averaging. Say you make $
100K in a single year, but the IRS lets you average that income over five years. From your perspective, you made $
100K up front; you've got $
100K in your pocket. From the IRS perspective, you made $20K that year, and you'll make $20K over each of the next four years. Which is real, $
100K all at once or $20K each of five years? You may say the former, since you've got $
100K now, but if you're talking taxes, the $20K/year is the "real" interpretation.
Likewise, funds and brokerages have their own rules for calculating holding periods.
These rules need not be consistent with each other or with tax rules. Typically, funds (a) waive short term redemption fees on shares purchased via div reinvestment (including cap gain divs), and (b) apply the redemption fee (e.g. 2%) only to those shares sold within the short-term period as opposed to all shares sold in the transaction.
In contrast to (b), brokerages typically charge a flat short term trading fee if
any of the shares sold are subject to the brokerage's short term fee. Fidelity, at least, explicitly waives fees on reinvested divs:
[Fidelity's short-term trading fee] does not apply to ... shares purchased through dividend reinvestment.
https://www.fidelity.com/bin-public/060_www_fidelity_com/documents/Brokerage_Commissions_Fee_Schedule.pdfFinally, to illustrate the difference that ordering rules make, consider the following transactions:
Jan 4 - purchase
100 shares
Nov 25 - purchase
100 shares
Dec 28 - div reinvest - purchase
10 shares
Jan
16 (next year) - sell
110 shares
On a strict FIFO basis,
10 shares (purchased Nov 25) will have been sold within 60 days of purchase. If
for the purpose of calculating a short-term redemption fee, reinvested divs are deemed to have been sold first, then the
110 shares sold will be the
10 purchased on Jan
16 and the
100 purchased on Jan 4. No fee will be assessed (assuming no fee is charged for redeeming div reinvestment shares).