1. Dollar-cost-average out of winners in fixed slices
The repeatable method
- Reject the false choice of "sell it all" vs "never sell." Instead, book profits incrementally — a fixed fraction (~25%) of the current position value at each meaningful run-up.
- Mirror the entry discipline: ease in on dips, ease out on strength; reinvest a trimmed slice if the stock pulls back to a clear support/breakout level.
- Accept you won't catch the top — the goal is "the middle 80%" at materially lower risk of round-tripping the gain.
Here: TSM from ~$84 (2022) to ~$303 — trimmed 25%-at-a-time; the simulated DCA-out returned 215% on the original $12,500 (~46% IRR) and captured nearly the same dollars as buy-and-hold, with less risk.
Watch for
- A position that has multiplied; each fresh run-up as the next 25%-trim trigger; a pullback to support as a re-add level.
2. Use price-to-sales, not just P/E, to know when a winner is expensive
The repeatable method
- Don't be reassured by a "reasonable" P/E alone on a high-growth name — a peak-margin P/E can look fine while the stock is wildly extended.
- Cross-check the price-to-sales ratio against the name's own 5-year history; an extreme P/S "leaves scant room for disappointment" even when the P/E looks okay.
- When both the company is dominant and the P/S is at a multi-year extreme, treat it as a sell/trim signal, not a buy.
Here: TSM's P/E ~20 "is not outrageous," but 13× sales "is way up there" — the basis for trimming despite its wafer-etching dominance.
Watch for
- P/S at the top of a name's historical range while P/E still looks tame — the hidden over-valuation tell.
3. Re-screen old "value" winners — a value stock that re-rated is no longer a value stock
The repeatable method
- Periodically re-run the valuation on names you originally bought as cheap — the original thesis expires once they re-rate.
- If a formerly cheap name now trades richly on P/S and P/E, downgrade it to trim regardless of how good the business is.
- Treat the whole sector as a warning when even its traditional value names are fully priced.
Here: GOOG (~$140 → ~$315) and XOM are now "very spendy"; "even the long-despised energy sector contains fully- to over-priced names."
Watch for
- A bought-cheap winner whose multiples have expanded to the top of their range; an entire value sector trading rich.
4. Let pervasive over-valuation set a portfolio-level cash target
The repeatable method
- Scan many of your holdings' valuation charts at once — when "so many" look extended, that's a portfolio signal, not a single-name one.
- Respond at the portfolio level: raise a deliberate cash buffer (here 20–25%) by harvesting the most-extended winners first.
- Keep selling rational, not reflexive — "don't look a gift stock in the mouth": harvest the gain rather than refusing to sell a winner.
Here: the breadth of expensive charts (TSM/GOOG/XOM) "concerns us… considerably" — the reason to raise up to 20–25% cash.
Watch for
- A majority of holdings at extended valuations simultaneously — the cue to lift cash, sourced from the priciest names.
5. Buy the multi-year breakout; trim into the subsequent parabola
The repeatable method
- Enter on a penetration of long-term overhead resistance (the "upside range expansion") — extend the chart window (six years vs the usual five) if needed to capture the level.
- Ride the breakout, but as the move accelerates well past the base, switch from add to trim — the breakout that justified the buy doesn't justify holding at any price.
Here: TSM's early-2024 six-year breakout was the buy signal (~$133); by ~$200 and again at ~$303 the same chart called for harvesting, not adding.
Watch for
- A confirmed multi-year breakout for entries; a parabolic extension far above the base as the trim trigger.
6. Sell tax-aware — prefer trimming inside tax-deferred accounts
The repeatable method
- Recognize the cost of the discipline: incremental trimming on the way up generates taxable gains in a taxable account.
- Where possible, run the trim-as-you-go process inside a tax-deferred account (e.g. an IRA rollover) to keep the after-tax result close to the gross.
- Factor the tax drag into the sell decision rather than letting it become a reason never to sell.
Here: the DCA-out matched buy-and-hold dollars ($36,652 on the original 119 shares) "unless these moves were made inside of a tax-deferred account" — taxes are the cost of the discipline.
Watch for
- Large embedded gains in taxable accounts; opportunities to run the trimming inside tax-deferred vehicles.