India VIX explained

India VIX is a volatility index published by NSE. It takes the prices of many NIFTY options and turns them into one number: how much NIFTY is expected to move over the next 30 calendar days, written as a yearly percentage. It is often called India's "fear gauge", because it climbs when traders rush to buy protection and falls when they relax.

The method is adapted from the VIX that the Chicago Board Options Exchange created for the US market. NSE uses the best bid and offer prices of out-of-the-money NIFTY call and put options across many strikes, from the nearest expiries, and blends them to a fixed 30-day horizon. Because it uses many strikes rather than one, it is a broad reading of implied volatility, not the IV of a single option.

What a VIX level means in points

A VIX of 14 means NIFTY options are priced for about 14% movement over a year, as one standard deviation. That is easier to use when converted to shorter periods:

Expected 1-day move ≈ VIX ÷ 19 · expected 30-day move ≈ VIX ÷ 3.5 (both in %)

The 19 is the square root of 365 days, and 3.5 is the square root of 12 months. With NIFTY at 25,000:

These are one-standard-deviation ranges. If NIFTY behaved like a textbook bell curve, it would stay inside them about two times in three. Real markets have more big surprise days than the bell curve allows, so treat the ranges as a guide.

A live example: India VIX today

Here is the current India VIX with its rank against the last year:

The level tells you how much movement options are priced for; the rank tells you whether that is high or low compared with the past year. The same VIX level can rank low after a volatile year and high after a calm one. The site also turns the NIFTY straddle into an expected move to the next expiry:

The straddle range covers the days until expiry rather than a fixed 30 days, so it will not match the VIX conversion exactly, but the two usually tell the same story.

How India VIX behaves

• It usually moves opposite to NIFTY. Sharp falls in NIFTY tend to bring sharp rises in VIX, because traders buy puts for protection. Slow rallies usually see VIX drift lower. The link is not perfect: VIX can rise with NIFTY before a big event.
• It tends to return towards its usual range. Spikes usually fade as fear settles, and very low readings rarely last for years. How long either takes is unpredictable.
• It rises before known events. Budget day, election results and major policy decisions usually lift VIX in advance, followed by a drop once the news is out (an IV crush for the whole index).
• It has extremes in crises. In severe sell-offs such as the 2008 financial crisis and March 2020, India VIX reached levels several times its calm readings. In quiet years it has spent long stretches in the low teens.

How traders use India VIX

• Judging option prices. A low VIX means NIFTY options are cheap compared with usual; a high VIX means expensive. Buyers prefer cheaper options; sellers collect more premium when VIX is high but take on more risk.
• Setting stop-losses and targets. When VIX is high, normal daily swings are bigger, so a stop placed for a calm market may be hit by noise.
• Sizing positions. Some traders trade smaller when VIX is high, because the same lot carries more rupee risk.
• Reading the market's mood. VIX is one input in the site's market mood score, alongside breadth and other measures.

VIX against the straddle and against real movement

India VIX, the NIFTY at-the-money straddle and NIFTY's actual movement are three views of the same thing:

• India VIX is a 30-day, many-strike view of what options expect, always on the same yardstick, so it is good for comparing one month with another.
• The ATM straddle is what the market charges right now for movement to one specific expiry. It is what traders actually pay or collect. The straddle insights guide explains how the site turns it into a range.
• Actual movement, measured as historical volatility, is what NIFTY really delivered. Comparing it with VIX shows whether options have been dear or cheap; see historical vs implied volatility.

When all three agree, the market is behaving as priced. When VIX is high but NIFTY is barely moving, option sellers have the edge for now. When NIFTY is swinging hard while VIX stays low, buyers are being paid more than they paid for. These are descriptions of the present, not forecasts.

A worked example: VIX before and after an event

Suppose India VIX sits at 13 a week before the Union Budget, rises to 17 the day before, and drops back to 14 the day after. A trader who bought a NIFTY straddle at VIX 13 and sold it at 17 gained from the rise in IV, whatever NIFTY did, minus the decay over those days. A trader who bought the same straddle at VIX 17 the day before needed NIFTY to move more than the higher price assumed, because VIX falling from 17 to 14 took away value the next morning. Same index, same event, very different results depending on when IV was bought.

Limits and common mistakes

• VIX is not a direction signal. A rising VIX often comes with falling prices, but not always, and it never says where NIFTY will go next.
• Low VIX is not the same as low risk. Calm periods can end suddenly, and option sellers are most exposed when premiums are thinnest.
• Reading VIX on expiry day too literally. VIX looks 30 days ahead, so it can stay high while the expiring options collapse, or stay calm while expiry-day swings are large. For the expiring contract, the straddle is the better guide.
• Comparing VIX with US volatility indices number for number. Each index reflects its own market; a level that is calm in one can be nervous in another. Compare India VIX with its own history.
• VIX covers NIFTY only. A stock can have very high IV around its results while VIX is calm. Check the stock's own options.
• Do not trade VIX levels mechanically. "Sell options when VIX is above X" ignores why VIX is high. Sometimes it is high because a large move is truly coming.

To compare VIX with the movement NIFTY actually delivered, read historical vs implied volatility.