BTC's Sep-25 72k Call OI Build Masks a $334k Seller Block
On its own, +294 contracts of 24h OI growth in BTC's September 72,000 call would normally get filed as call accumulation. The aggressor data says otherwise: taker net premium at that strike is -$260,725 over the past day, buyerAggression sits at just 0.22, and one flagged block trade sold 250 contracts for $333,951 in premium (~$15.5M notional) in a single hour — the dominant seller print across the whole Sep-25 book (z=37.7 vs baseline). OI still rose because the block opened fresh short exposure rather than closing longs; someone wrote size into strength rather than chased it.
Nearby strikes tell a more mixed story — flow is buyer-led at 70000 and 74000, seller-led at 60000, 65000, 72000 and 75000:
| Strike | 24h OI Δ | Net Premium (24h) | Buyer Aggr. | Blocks |
|---|---|---|---|---|
| 60000 | +32 | -$189.7k | 0.00 | 2 |
| 68000 | -24.9 | +$54.3k | 0.80 | 0 |
| 70000 | +91.5 | +$400.6k | 0.76 | 3 |
| 72000 | +294 | -$260.7k | 0.22 | 1 |
| 74000 | +32.8 | +$27.5k | 0.78 | 0 |
| 75000 | +16.2 | -$29.5k | 0.16 | 0 |
No liquidations were involved in the 72000 print — this was a deliberate, size-driven premium sale.