Implied Volatility: What the Options Market Expects

[Fairman]

Implied Volatility: What the Options Market Expects

Options prices contain information about expected future movement. Implied volatility is the volatility level that makes an option's theoretical price match its market price.

Higher implied volatility means the market expects bigger price swings, and options cost more. Lower implied volatility signals expected calm. It is usually quoted as an annualized percentage, so a reading of 8 percent for EUR/USD over one month implies a typical monthly move of roughly 8 divided by the square root of 12, or about 2.3 percent.

You can convert implied volatility into expected daily ranges. Divide the annual figure by roughly 16, the square root of the number of trading days, to estimate the one-day standard deviation. An implied volatility of 8 percent suggests a daily standard deviation of about 0.5 percent, which on a rate of 1.10 is around 55 pips.

Why does it matter for traders? Implied volatility rises before scheduled events, like central bank meetings, and falls afterward. A jump in implied volatility without an obvious event may signal that large players are hedging or expecting a move.

It also helps set expectations for stop and target sizes. If implied volatility is low, a wide target may be unrealistic.

Data is available from many providers, often as volatility indexes for major pairs.

Practical step: find the one-month implied volatility for your main pair, and compute the expected daily move in pips.

[Fairman]

The divide by 16 trick is really handy. Takes ten seconds and gives you a rough idea of a normal day, which is great for checking if your target is realistic. If one month implied vol on GBPUSD is 9 percent, the daily figure is about 0.56 percent, which at 1.30 works out to roughly 73 pips. That's a one standard deviation move, so about two thirds of days should stay inside it. If your plan needs a 100 pip move in one session on a normal day, you're asking for something unusual. It doesn't mean it can't happen, just that the target is ambitious and the trade will often need more time than you think.

[Fairman]

Watch the jump before big meetings too. If one week implied vol is well above one month, the market expects that event to do the moving, and things may calm down after it. That's useful for planning. In the days before a big central bank decision, price can be quiet as people wait, and breakouts often fail. After the decision, volatility can drop as the uncertainty clears. Where I find it most useful is spotting when vol rises without any obvious event in the calendar. That often means something is brewing, maybe political risk or stress in other markets, and it's a good prompt to cut size and check the news.

[FXS Prop Desk]

The conversion in the example can be made more general: dividing the annualised implied volatility by the square root of the number of trading days in the period gives the expected one-standard-deviation move. For one day, that is about 8% / 16 = 0.5%. Comparing that with the realised daily range is a quick way to see whether options are pricing more or less movement than the market is actually delivering.

[Shadow Trader]

One caution on comparing implied with realised, as FXS Prop Desk suggests: make sure both sides measure the same thing. Implied volatility describes close to close movement, while most of us look at the daily high to low range, which is naturally bigger.

For a random walk the expected high to low range is roughly 1.6 times the one day standard deviation. So the 55 pip figure from the 8 percent example lines up with an average daily range of about 88 pips, and ranges near 88 do not mean options are underpricing anything.

The same square root logic scales down to a scalper's window. If those 55 pips were spread evenly through the day, one hour would carry about 11 pips, which is 55 divided by the square root of 24.

They are not spread evenly, and that is the useful part. A quiet Asian hour might deliver a fraction of that 11 while the London open hour delivers double, so a 10 pip target can be routine at 8am Lagos and ambitious at 3am.

Fairman, do you adjust for the event premium when a central bank meeting sits inside the one week figure? Stripping it out would make the ordinary days look calmer than the headline number.

[Shadow Trader]

One thing that trips people up when comparing implied with realised is that implied usually runs a little higher on average. Option sellers want paying for the risk of a sudden jump, so a gap of a point or so in favour of implied is the normal state rather than a signal.

Say one month EURUSD implied is 8 percent and the last month has actually delivered 6.5. That is about 45 pips a day of close to close movement against the 55 the options suggest, which describes a calm market priced roughly as usual.

The reading worth noticing is the reverse, when realised climbs above implied for more than a few days. If 10 percent is being delivered against 8 implied, option sellers are losing money, and implied tends to get marked up quickly to catch up.

For a scalper that rarely changes an entry, but it changes what a normal day looks like. On 10 percent the same divide by 16 rule gives roughly 69 pips a day at 1.10, so stops sized for the calm month start getting clipped by ordinary noise.

Has anyone here tried using that crossover as a size filter? Cutting risk when realised has been above implied for a week seems sensible, though I have not seen it tested properly.

[Shadow Trader]

Options prices embed the market's expectation of future volatility. For major pairs, implied volatility for one-week or one-month options is published by several data sources, and it moves with events and sentiment.

For scalpers, the number doesn't produce entries, but it provides context. Rising implied volatility ahead of a major event suggests larger moves are expected. Falling implied volatility in a quiet summer suggests narrower ranges, and that targets may need to shrink.

A rough conversion turns annualized implied volatility into an expected daily range. Divide by the square root of the number of trading days in a year (about 16), and the result is the one standard deviation daily move in percent. Converting that to pips gives a benchmark. Actual ranges well below the implied number hint at a quiet day. Ranges beyond it suggest an event-driven session.

A quick rule of thumb many use: if realized range exceeds the implied daily range for several sessions in a row, volatility is running hot and implied levels are likely to rise. If realized falls well short, options are overpricing movement.

Anyone following implied volatility, which source is used, and has it changed how targets are set?

[WhitG47]

Shadow Trader, before I say which source I use... how did you get on with that realised-above-implied filter, did you ever actually run it on your own trades? Mind you, I can't be bothered with anything that needs a spreadsheet and three data feeds, so I'm curious what teh setup looks like when it works for you.

G.

[FTtrader]

Shadow Trader, before I say which source I use... how did you get on with that realised-above-implied filter, did you ever actually run it on your own trades? Mind you, I can't be bothered with anything that needs a spreadsheet and three data feeds, so I'm curious what teh setup looks like when it works for you.

G.

Yeah good question, im curious too

[WhitG47]

Yeah good question, im curious too

Same here... and I suspect the answer will be that it only works if it's lazy enough to survive past a fortnight. Years back I kept a scrappy notebook of daily ranges next to the implied figure, and it lasted about three weeks before I couldnt be bothered, mind you the little I did log made me size stops wider for a while.

If Shadow Trader has it down to one number and a glance, fair play to him.

G.