Position sizing is one of those things that separates traders who last from traders who blow up — and most people starting out sell way too many contracts at once. A good starting rule: risk no more than 5% of your total trading capital on any single CSP position.
Let me make that concrete. Say you have $50,000 in your wheel account. Five percent is $2,500. If you're selling puts on AAPL at a $175 strike, each contract controls 100 shares, so your max obligation per contract is $17,500. That's already 35% of your account on one position — which is why most people with a $50k account shouldn't be selling more than one or two AAPL contracts at a time, full stop.
The 5% rule is a guideline, not gospel. Your actual number depends on a few things: how volatile the underlying is, how far out your expiration is, and whether you're comfortable potentially owning 100 shares of that stock at the strike price. That last part matters more than most people think. Every CSP you sell is a promise to buy 100 shares. If you sell three contracts on NVDA at a $450 strike, you're on the hook for $135,000 worth of stock if it tanks through your strike. Can your account handle that assignment? Can your psychology handle it?
The contract count math people actually use
Here's a simple framework. Take your total capital, decide what percentage you're willing to tie up in any one position (most experienced wheel traders use 10-20% per position), and divide by the buying power requirement for one contract.
If you have $80,000 and want no more than 15% per position, that's $12,000 per position. Selling a put on SPY at $480 requires about $48,000 in buying power for one contract in a cash-secured account. That doesn't fit your 15% rule at all — which tells you SPY might not be the right underlying for your account size, or you need to go to a lower strike.
Now look at a stock like Ford (F) at a $12 strike. One contract requires $1,200 in buying power. Your $12,000 allocation could technically support 10 contracts. But selling 10 contracts on a single name is still concentration risk, even if each contract is small. Most traders I know cap at 5 contracts per position even when the math technically allows more.
Volatility changes the calculus
High-IV environments tempt you to go bigger because the premiums are juicy. Don't. When implied volatility is elevated — like NVDA during earnings season or any stock after a major news event — the market is pricing in larger expected moves. That premium looks attractive because the risk is real. Selling 5 contracts when IV is 80% is not the same as selling 5 contracts when IV is 30%, even if the dollar premium looks similar.
A practical adjustment: in high-IV environments, cut your normal contract count in half. If you'd normally sell 3 contracts on a position, sell 1 or 2. You're still collecting meaningful premium, but you're not loading up right before a potential big move.
The assignment problem
Here's where new wheel traders get caught. They size based on premium collected, not on assignment risk. You sell 4 puts on META at $300 because the premium is $800 per contract — that's $3,200 in a week, sounds great. Then META drops 15% and you're assigned 400 shares at $300, which is $120,000 in stock. If that's more than half your account, you're now running a concentrated position in one name and your wheel is stuck.
The question to ask before you enter: "If I get assigned on every single contract I'm selling right now, what does my portfolio look like?" If the answer makes you uncomfortable, reduce the contracts.
A real sizing example
Say you have $60,000 and you want to run the wheel on three tickers — AAPL, AMD, and GOOGL. You allocate 20% per position, so $12,000 each. AAPL at a $170 strike requires $17,000 per contract — that's over your allocation, so you either skip AAPL, go to a lower strike, or accept that this is a one-contract max. AMD at $110 requires $11,000 per contract — fits your $12,000 box, one contract. GOOGL at $160 requires $16,000 — again over budget, skip or adjust.
That's a boring portfolio. One contract here, one there. But it's survivable, and survivability is what keeps you in the game long enough to actually compound.
What to actually do today
Pull up your current open CSP positions and run the assignment math. Add up the total buying power required if every single contract got assigned simultaneously. If that number is more than 60-70% of your account, you're over-extended — and the next market down-move will show you exactly why. Trim one position, bank the premium you've already collected, and resize from there.
Start conservative. You can always add a contract next week. You can't un-assign 500 shares of a stock that just dropped 20%.