Who this is for — Traders who want derivative exposure without managing expiry. Perps mirror spot with leverage; carry comes from funding, not roll.
A perpetual future (perp) is a derivative with no expiration date: longs and shorts stay open until you close or get liquidated. Contract price is pegged to cash via the funding rate — periodic payments between sides.
In plain terms — A future that never expires. Instead of quarterly roll, every 8 hours (typical crypto) longs and shorts exchange a «rent» to keep price near spot.
Perp vs classic future
| Element | Classic future | Perpetual |
|---|---|---|
| Expiry | Yes — roll required | No |
| Cash alignment | Basis + roll | Funding rate |
| Carry cost | Roll + basis | |
| Typical markets | Index, CME commodities | Crypto (BTC, ETH…) |
On traditional futures, expiry structures liquidity and roll; on perps liquidity stays on one ticker, but carry is explicit and visible.
Funding mechanism
- Positive funding → longs pay shorts (perp above spot)
- Negative funding → shorts pay longs
- Frequency: often every 8h on crypto venues; formulas vary by exchange
Funding is not a broker fee: it is peer-to-peer transfer that incentivises spot–perp arbitrage.
Common mistake — Holding for days at extreme funding without modelling carry — chart flat, P&L still bleeds.
Example — Long BTC-PERP, funding +0.05%/8h, 3-day hold (9 periods). Carry ≈ −0.45% on notional, regardless of price move.
Summary card
- What: no-expiry derivative, margin + leverage.
- Cost: funding + fees + slippage.
- Check: expected funding before opening a hold.