What LTP tells you, when to trust it, and why it's the noisiest column on the chain.
LTP = Last Traded Price. The price at which the most recent trade in this option happened. It's the headline number on every option chain.
But LTP can be 30-60 seconds stale, especially on illiquid strikes. Sometimes the bid-ask spread is more informative than the printed LTP.
ATM strikes on liquid indices (NIFTY, BANK NIFTY) update every few seconds during market hours. LTP here is close to mid-market.
OTM strikes update less frequently. Far OTM (>5% from spot) on NIFTY weekly can have LTP stale by minutes.
Stock options have lower turnover. LTP can lag much more than index options.
If LTP is between bid and ask: trustworthy.
If LTP is below bid: stale (recent trades moved the market up).
If LTP is above ask: stale (recent trades moved the market down).
Always cross-check before placing limit orders — using yesterday's LTP gets you nowhere.
For NIFTY/BANK NIFTY ATM strikes during market hours: 1-3 seconds. For far OTM strikes: 30 seconds to minutes. For stock options: can be 5-15 minutes on illiquid strikes.
Closing price is a calculated value (weighted average of last 30 min trades on settlement day). LTP is just the most recent trade — different concepts.
Strike has had zero trades today — extremely illiquid. Bid-ask still exists but no actual trades have happened. Avoid trading these strikes.