How to flip Marble block in OSRS

Flipping Marble block on the Old School RuneScape Grand Exchange currently makes about -4,083 gp profit per item after the 2% GE tax: buy near 339,243 gp (the instant-sell price) and re-list near 341,999 gp (the instant-buy price).

• Buy at (instant-sell): 339,243 gp
• Sell at (instant-buy): 341,999 gp
• Margin after 2% tax: -4,083 gp (-1.20% ROI)
• Buy limit per 4 hours: 11,000
• 24h volume: 3,618 (liquid)
• Max profit per limit cycle: -44,913,000 gp on 3,731,673,000 gp of capital

The flip, step by step

1. Place a buy offer at or just above 339,243 gp (the current instant-sell price).
2. Wait for the fill. Marble block is liquid right now, so expect fills within the hour at reasonable prices.
3. Re-list at or just below 341,999 gp (the current instant-buy price).
4. The GE takes 6,839 gp tax (2%) per item when it sells, leaving -4,083 gp profit each.
5. Repeat up to the buy limit (11,000 per 4 hours), a full cycle is -44,913,000 gp on 3,731,673,000 gp of capital.

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