Perpetual swaps have no expiry, so something has to keep their price anchored to spot. That something is the funding rate — a periodic payment between longs and shorts that drags the perp back toward the index.

The mechanism

Funding is exchanged directly between position holders, not paid to the venue. Most exchanges settle every 8 hours, three times a day.

  • Positive funding: perp trades above index. Longs pay shorts. The cost of holding leverage long rises, nudging the perp back down.
  • Negative funding: perp trades below index. Shorts pay longs. Holding shorts gets expensive, nudging the perp back up.

The headline number is usually quoted per 8 hours. Annualize it to feel the weight: a steady +0.01% per interval is roughly +11% a year — trivial. A sustained +0.10% is ~110% annualized, which is a tax that ends trends on its own.

The two components

The rate is interest plus a premium. The interest piece is small and roughly fixed. The premium does the real work: it tracks how far the perp's price sits above or below the underlying index across the interval. When perps run hot, the premium dominates and funding spikes.

How to read it

Funding is a positioning gauge, not a directional signal on its own. Persistently high positive funding means crowded longs paying to stay in — fuel for a long squeeze on any dip. Deeply negative funding means crowded shorts, and the setup for a short squeeze.

The actionable read is change, not level. Funding flipping from strongly positive to neutral while price holds is a positioning reset — leverage flushed, trend often healthier afterward. Funding pinned at extremes is a warning that the move is rented, not owned.

Cross-venue nuance

Funding is set per venue, so it diverges. A perp running +0.08% on one exchange while another sits near zero says the crowding is venue-specific — often retail-heavy books — and the gap is itself an arb. Aggregate, OI-weighted funding is the number to anchor on; a single venue's print can mislead on where systemic leverage actually sits.

Takeaway

Funding keeps perps tethered to spot by paying the crowded side to leave. Annualize the number, watch the premium component, and treat extremes as squeeze risk rather than confirmation. The reset is usually a better entry than the extreme. And never read funding in isolation from OI — high funding on flat OI is froth that bleeds out; high funding on rising OI is a building position that can snap.