My Fractional Dividend Reinvest Kept $0.0041 Per Share — Across 40,000 Shares, I Asked Why

The spreadsheet was open at 7:15 in the morning, before my kids woke, because I had promised myself I would reconcile our brokerage account the way I reconcile our grocery budget. Row by row, dividend by dividend. By the third cup I was staring at a column of numbers that should have been zero and were not.

Every reinvestment on our largest position, a boring industrial ETF we had built up over nine years, snagged slightly fewer shares than the dividend math said it should. Not a few cents short. A fraction of a cent per share, per quarter, systematically, invariably in the same direction. Down.

the fourth decimal place where money hides

a $3.40 quarter, every quarter

Here is the mechanism, laid bare. A dividend of $0.6287 per share lands on 40,000 shares. That is $25,148.00 of income, clean. The reinvest buys stock at, say, $91.42, which mathematically entitles you to 275.0841 shares. But the platform rounds your purchase to four decimal places, truncating rather than rounding up, and the crumbs do not sit in a cash bucket waiting for you. They evaporate. Per quarter. On every position. Forever.

One quarter of leakage on this position came to approximately $3.40. A year, about fourteen dollars. Nine years of holding, and the cumulative skim on this single position crossed into three figures. Trivial per event. The pattern was what bothered me, cuz the direction was never random. Fractions round down with the reliability of gravity.

Most people will read fourteen dollars a year and shrug. I nearly did. What stopped me was multiplying by the customer base of a firm with eleven million accounts, and then I stopped shrugging.

nobody's statement shows a line for this

I called the service line expecting a quick explanation. The first representative was kind and had no idea what I was describing. The second one found the rounding policy in an internal document and read it to me, verbatim, including the phrase "residual amounts are not retained for customer credit." Not retained. My crumbs, swept.

She was not wrong about the scale. Fourteen dollars a year per account is not a business model, it is dust. But dust at eleven million accounts is a number with real digits, and more to the point, the disclosure lived in a document nobody reads, phrased so gently that reading it would not have helped.

I asked for the adjustment anyways. Full disclosure of my motives: I did not need fourteen dollars. I wanted to see what the machine says when you ask it to notice its own dust.

the letter I did not expect

the answer, in writing

Ten days later a written response arrived, and credit where due, it did not stonewall. The firm credited my account $61.28, which covered two years of reconstructible rounding leakage, and pointed out that older records were archived in a format that could not be audited share-fraction by share-fraction. They also flagged something I had missed: on two quarters, the reinvest price used was the volume-weighted average of the morning, not the closing print, which had cut in my favor by a few dollars net.

So the honest total was closer to fifty dollars owed, they paid sixty-one, and I closed the ticket feeling stranger than anticipated. Vindicated and slightly embarrassed at once. The system had answered, slowly, in writing, with a surplus.

Then I reckoned about the people who would never write that letter. The rounding is regressive in a quiet way. It scales with position size, so it takes the most, in absolute terms, from the largest savers, but as a share of wealth it nicks the modest accounts hardest, cuz fourteen dollars means something different to a portfolio of six thousand than to one of six hundred thousand. And the customers least likely to audit a fourth decimal place are exactly the ones the dust costs the most, in spirit if not in dollars.

what reinvest drag actually adds up to

I went looking for whether anyone had studied this, and the honest answer is that the leakage is real but tiny against the things that actually decide your returns. Expense ratios, behavioral selling, asset allocation. Reinvest rounding sits three orders of magnitude below the fee on a typical index fund, and I will not pretend my crusade moved my family's net worth.

What it moved was my standard for platforms. When I later compared brokers for my daughter's custodial account, the rounding policy became a tiebreaker question I asked every sales rep, and watching them scramble to find the answer told me plenty. One firm, to its credit, rounds reinvestments up to the fifth decimal and credits residuals to the cash sweep. It got the account. A $14 annual detail decided where a child's money will sit for fifteen years, which is either absurd or exactly right.

the small print I read differently now

The experience rewired how I read platform disclosures generally. The words that matter are the ones describing what happens to fractional remainders, uninvested cash, corporate action proceeds, the residue of automation. Anywhere a machine splits money into pieces, ask where the crumbs go. The answers are ordinarily legal, ordinarily disclosed, and typically written by the side that keeps the dust.

I still reinvest dividends automatically on the hefty position. The math still favors it overwhelmingly against holding cash, rounding or no rounding; the drag is a rounding error's rounding error. This was never about optimizing pennies into performance. It was about finding out whether asking works.

the receipt I keep in the drawer

The $61.28 credit sits in the account history with a reference number I screenshotted, next to the two-page letter. My husband thinks the frame idea is a joke. It is only half a joke.

Here is what I would tell the version of me who opened that spreadsheet at 7:15 with a cup of coffee and a suspicion. Ask. Write the polite, tedious letter with the row-by-row table attached. The worst outcome is a form letter and fourteen dollars of confirmation. The best outcome is a written answer, a credit, and the discovery that the system will, when pressed by exactly the right kinda annoyance, admit its own dust exists.

And if nobody ever asks, the dust just keeps drifting down, quarter after quarter, into a place no statement line will ever name.