How to flip Iron cannonball in OSRS

Flipping Iron cannonball on the Old School RuneScape Grand Exchange currently makes about 2 gp profit per item after the 2% GE tax: buy near 13 gp (the instant-sell price) and re-list near 15 gp (the instant-buy price).

• Buy at (instant-sell): 13 gp
• Sell at (instant-buy): 15 gp
• Margin after 2% tax: 2 gp (15.38% ROI)
• Buy limit per 4 hours: 11,000
• 24h volume: 1,025,051 (extremely liquid)
• Max profit per limit cycle: 22,000 gp on 143,000 gp of capital

The flip, step by step

1. Place a buy offer at or just above 13 gp (the current instant-sell price).
2. Wait for the fill. Iron cannonball is extremely liquid right now, so offers at fair prices typically fill within minutes.
3. Re-list at or just below 15 gp (the current instant-buy price).
4. The GE takes 0 gp tax (2%) per item when it sells, leaving 2 gp profit each.
5. Repeat up to the buy limit (11,000 per 4 hours), a full cycle is 22,000 gp on 143,000 gp of capital.

Margins move constantly. Re-check the live Iron cannonball numbers and price chart on GrandExchange.com right before committing.