Every wheel trader starts with a spreadsheet. A few columns, some simple formulas, maybe a chart or two. It works great — for the first 20 trades. Then you roll a position, or you get partially assigned, or you try to add a second ticker, and suddenly nothing adds up anymore.
The problem isn't that you built it wrong. The problem is that spreadsheets were never designed for the kind of multi-step, campaign-based accounting that the wheel strategy requires. Here are the seven most common ways they break — and what actually causes each failure.
1. Rolling Trades Corrupt Your Formulas
When you roll a CSP from a $170 strike to a $165 strike for a net credit, you're executing two transactions: a buy-to-close and a sell-to-open. Most traders record this as a single row to keep things clean. That decision will haunt them later. Your SUM formulas now include a phantom closed trade. Your position count is off. And your ACB calculation is drawing from the wrong rows.
The right approach is two separate rows tagged with a shared Roll ID — but even that creates new formula complexity that most people underestimate until it breaks.
2. Assignment Events Require 5 Manual Updates at Once
Getting assigned sounds like a simple event. In your spreadsheet, it's anything but. You need to simultaneously close the put position, open a new stock position, link all prior CSP premiums to the new stock's cost basis, update your open positions tab, and recalculate your campaign ACB. That's five interdependent manual operations. Miss one and every subsequent calculation in that campaign is wrong — often by hundreds or thousands of dollars.
3. Circular Reference Errors Kill Running Totals
Running total formulas are inherently self-referential. The moment a cell references another cell that references back to it — extremely common in cumulative ACB calculations — Google Sheets throws a #REF! error and your entire tracking model freezes. You can work around this with iteration settings or helper columns, but most traders don't know how and end up with static values pasted over the broken cells. That's not tracking — that's just writing numbers down.
4. Timezone Mismatches Break Expiration Dates
If you're trading US options from outside Eastern Time — which applies to a huge number of active wheel traders in Canada, the UK, India, and Australia — your trade timestamps can land on the wrong calendar day. A Friday 4 PM ET expiration shows as Saturday in IST. Your DTE calculations are off by one day everywhere. It seems minor until your "3 DTE" alert fires when you actually have 2 DTE and you miss a roll window.
5. Partial Assignments Break Position Sizing Everywhere
You opened 5 contracts. Two got assigned, three expired worthless. Now you need to split your premium history pro-rata between the 2 assigned contracts and the 3 that closed. Every formula that references "your CSP premiums" needs to know which portion belongs to which outcome. Building that split correctly in a spreadsheet requires array formulas most people have never written, and getting it wrong means your ACB and your realized gains figures are both incorrect — which matters at tax time.
6. Multi-Currency Positions Drift Further From Reality Each Week
If you wheel a mix of US and Canadian stocks, or trade US options from a non-US account, you need FX conversion on every premium, every cost basis, and every P&L figure. A static exchange rate baked into your formulas in January is noticeably wrong by June. And because FX errors are subtle, they often go undetected for months — until your total portfolio return is off by several percentage points from what it should be.
7. One Accidental Edit Can Wipe Months of Data
This one needs no explanation. You've been there. A misplaced paste, an accidental row delete, a formula accidentally typed over a value. Google Sheets has version history — but finding and restoring one specific corrupted cell from 90 days ago is genuinely painful and often incomplete.
So What's the Fix?
Every problem above has a clean solution in purpose-built options tracking software. OptionWheelTracker handles rolls, assignments, partial fills, and multi-currency conversions natively. ACB recalculates automatically after every trade entry. Your data is cloud-stored with no risk of a stray keystroke deleting three months of history.
Your spreadsheet served you well through your learning phase. Most serious wheel traders outgrow it around trade 20-30. The question is whether you wait for a costly formula error to make the switch for you.