Need help re: stress-testing my acct Margin (incl option spreads) based on changes in underlying SP

R

Rhiinoo

I'm looking for a tool / resource that would let me model what various hypothetical movements in an underlying SP would do to my account's margin requirements. I have an Excel formula that calculates option margin requirements, BUT only for straightforward naked long/short puts and calls...my account has several more complicated option spread positions that have hairier margin calc's including offsets, etc. (e.g. if I'm long both a put and a call in same underlying, I requires lower margin than if each position were naked b/c they offset / "protect" each other).

Why I want this: I was once very surprised to find that a relatively minor premarket move in an underlying (+4%) had a drastic effect on my margin: I went to bed with very comfortable excess margin and awoke to find that I was in a $5K margin *deficit* (all because of a relatively small move in the underlying.) I'm trying to 'get out in front' of such a scenario going forward, so I want to play around with various hypothetical price movements on the underlying to see what they would do to my margin levels so that I know how sensitive my current portfolio is to underlying price changes.

I use IB, so a native IB tool would be best (since I wouldn't have to input my existing positions) but I don't think they have one (an IB chat rep said that the Risk Navigator might allow me to do this, but wasn't sure.)

Any suggestions?
 
Overnight said:
I am not sure if this will be of help (PC-SPAN). I downloaded it and it was way too tedious (for me at least) to go through. But it seems to be very thorough once all correct data is loaded up.

http://www.cmegroup.com/clearing/risk-management/span-overview.html#spanProductSuite
More...

Thanks for the link, but it seems like only 1 of the 2 products they offer would allow any sort of hypothetical / stress-testing / modeling. And that product costs $3,000. The free product only calculates margin requirements for a given portfolio...and IB's TWS software obviously already does that. But I need a little more functionality...specifically the ability to say "OK, what would a x% rise/fall in the underlying SP do to my margin situation?" Seems like only the $3K product would allow for that (a little exp for me).
 
Many ways to skin this particular cat.
If you google "delta-gamma approximation" you'll find a *boatload* of solid information, including a delta-gamma-theta deal:
Δ(V) = Delta * Δ(X) + 0.5 * Gamma * Δ(X)2 + Theta * Δ(T)

I went a shade further, and included a percent change in volatility for each point of delta, and got (the attached pdf) for overnight use. The expirations run from red (shortest) through yellow and into green (longest) so that, with a single look, I can see what expiry needs attention, and which side. (The portfolio being the heavy black sum.)

If you were to put your underlyings in a particular order, that might be a format that would work nicely.
 

Attachments

Not sure to whom you're replying, JackRab, but the IB tools I've seen are mostly mallets looking to bonk elephants into submission -- ranging through ±5%, 10%, etc.
That's a range that might be the most-consistent mix for individual equities, but for large-dollar index positions, that size movement gets labels like "correction" and "bear-market" and outright "*Depressionnnnnn*!". Yowsa.

As well, for my own overnight use, ±1% is a once-or-twice a year event, with the vast majority being ±0.25% or less. It's been in daily use for ~6months now, and it's been hugely accurate, in overall portfolio effect, and in divining which expiry+direction needs attention first/most. I just figured out how to drop a .png with a couple of keystrokes. {"Sheesh!" :rolleyes: }

OvernightPortfolioRiskCapture.PNG



With regard to margin sensitivity, I don't consider it except in entering positions: i.e., I always know how much I have "@Risk" in Overnight Margin -- that being the most trouble that could be had. If the market drops catastrophically overnight (as has happened, right?), I know beforehand what my losses would be before I open TWS.

Lastly, with regard to usage, the heavy-black portfolio [summation] line can be thought to center on 0% as "desirable" -- or at least indicative that the account is not biased to a market move in either direction. (Portfolio delta ≈ $0 ±$20). Today, I am working on buying back [canary yellow] Nov17 puts and selling those capital slots further up towards the market -- that load would turn the Nov17 line down sharply on the graph's left side.
 
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tommcginnis said:
Many ways to skin this particular cat.
If you google "delta-gamma approximation" you'll find a *boatload* of solid information, including a delta-gamma-theta deal:
Δ(V) = Delta * Δ(X) + 0.5 * Gamma * Δ(X)2 + Theta * Δ(T)

I went a shade further, and included a percent change in volatility for each point of delta, and got (the attached pdf) for overnight use. The expirations run from red (shortest) through yellow and into green (longest) so that, with a single look, I can see what expiry needs attention, and which side. (The portfolio being the heavy black sum.)

If you were to put your underlyings in a particular order, that might be a format that would work nicely.
More...

(Market down SPX 12.5pts -0.50%; volatility pops to VIX=11)
"Yeah. Yeah. A volatility point move for every % of delta move."
It may not be happy news, but damn, it's accurate.
 
JackRab said:
Doesn't IB's risk tool do that? Risk Navigator? It also gives Margin Sensitivity...
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FYI after playing around with custom What-If scenarios in RN, and a fair amount of back and forth with IB, it appears that it's NOT possible to see potential margin impact of changes in the underlying prices, etc. A frustrating limitation, since it seems rather straight-forward...all RN will do is model what changes in the underlying price will do to your P&L / overall portfolio value, but even though they show your account's current Margin / Excess Liquidity at the top of the RN What-If window, that figure does not update to reflect your hypothetical changes.
 
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