Wiki Selling TSLA Options - Be the House

[ReddyLeaf]

A question - mostly rhetorical - but something for everybody to be thinking about that seem to be getting closer and closer ATM in their trades (which has include me especially with 725 strike calls, but also on the put side):

Are we pulling in closer to the share price due to technical analysis that leaves us highly confident in what will happen with the share price, or is this also at least partly driven by a premium / credit result we are seeking? The shrinking IV should make for smaller and smaller credits assuming reasonably constant distance from the share price.

Personally, I have been creeping closer to ATM (actually I’m selling ATM puts now because I’m willing to take the shares) because of 1) ten months of experience, 2) finally keeping a significant amount of cash available for buybacks, 3) balancing call-put sales around 4:1, 4) watching/learning from you and @Lycanthrope and, specific to this week, 5) having a very high confidence that the weekly SP will remain between 700 and 750 (MaxPain). Also, I’ve been modestly successful with timing my sales to local maximum (calls) or minimum (puts). When properly timed, they drop in value quickly enough that I feel comfortable letting them ride. Improperly timed, well, that‘s what the extra cash buyback-roll is for. Since I‘m living off of other income, and I have many years before I can access these IRA accounts, I don’t really have a specific premium target, though lately it has been $4–$8. Months ago I was happy with $2-$4 premiums, now I’m just happier. All of the profits eventually go into buying 5-10 shares per week. My original goal was to add 100-200 additional shares this year, which I have exceeded by judicious small purchases below MaxPain every week. As for increased risk on an IV jump, well I’ve already lost call shares below $650, been put shares at $800 when the SP was $620, and any number of prices in between. I’m certainly not perfect, but getting paid to learn (and learning with a lot of mistakes) and been fun and challenging. All of my trades are fully cash- or share-backed, no margin or leverage, so it’s all really just turning the wheel. If the SP runs away from me, well, then I just lose out on some future appreciation. I’ll continue to sell puts ATM and make 1%/wk (>50%/yr is pretty good interest) until the SP pulls back. On the other hand, I will immediately buyback any calls that I can when the annual meeting date or stock split is announced. I don’t want to have sold calls during the annual meeting.

 

[CHGolferJim]

Hey guys-

This week I started day trading TSLA covered calls. Following the discussion above, the premiums these days are too low for my liking considering the potential for a gap up any day now.

I am selling cc’s into rapid price rises and buying back on the reversal.

today’s trades - all the same contract:
STO $740c 8/20 for $6.10 @9:32 AM
BTC for $5.10 @9:37 AM

STO for $5.50
BTC for $4.60

STO for $4.60
BTC for $4.50

So I made $2.00 per share on these trades today.

glta

Pretty good. Try selling cc for a week or 2 out at $5-$15 premium depending on strike and IV, and rolling as needed. Can probably net $5+/week once you get the hang of it. NOT advise.

 

[JustMe]

Pretty good. Try sell cc for a week or 2 out at $5-$15 depending on strike and IV, and rolling as needed. Can probably net $5+/week once you get the hang of it. NOT advise.

Thanks, Jim
That’s what I’ve been doing for a while. I just don’t want to get blasted by a gap up and stuck waiting for two months ‍

 

[adiggs]

@adiggs

Do you not get worried about an event or announcement that could rally the stock?

When you go further out on your CCs, do you sell further OTM? Or do you use the same criteria that you would use for a regular weekly CC?

I find there is a certain amount of comfort staying within 2 weeks until expiration to be able to manage a surge in the stock price.

There is a balancing act here for sure. I like being in the weekly range for the much more frequent strike adjustments they provide. My own research tells me that the incremental work of 2 weeklies vs. 1 every other week option is worth about 10-30% more total, so I earn more on the weeklies. (It's imprecise that research - good enough for me, but you'll want to do your own instead of trust mine ).

When I go to later expirations I naturally get more distant strikes. If I'm using delta to position the strike then it gets me 740s next week vs 725s this week for example when I opened those positions. I also tend to look at similar technical criteria for choosing strikes, while also realizing that put/call wall and max pain information is, IMHO, nearly useless until the week of expiration. If you've watched that data very much then you've seen that a call wall next week is typically <10k contracts, while a call wall this week is much higher and sometimes >100k contracts.

My technical indicator toolkit isn't yet well enough developed to be able to say much about next week.

And that more frequent adjustment period is what might also draw me back into weeklies


I do worry some about announcements that rally the stock, but not nearly as much as you might thing. This is mostly due to how I've got my CC strategy setup now, and I really like it. The first component is that I'm only selling lcc's these days. I still own shares, though I own a lot fewer shares now than I have previously. Actually not as many fewer now that I think about it, but my focus is on owning leaps that I use to sell lcc's with.

My preference is that they don't assign, but my larger mental model and attitude is that those owned leaps are owned for income purposes. If I do "take assignment" (see previous posts about what that actually means) though, then that's just fine as it'll almost certainly be a big contributor to income. In fact, the net result is that if I can roll my CC strikes fast enough to keep up with the share price, then I've actually expanded my exposure to sustained moves up, all in the name of "income"

SO - since its income, if the shares were to move fast and I could only roll up to the 800 strike, I'll be excited about the income production from selling at 800 plus the large (for me) credits from selling the cc, instead of disappointed about all of the money left behind by selling at 800 when shares are at 1000.


My other management technique that I've used previously on announcements that I was very good at - the day of teh S&P announcement, I immediately closed all of my open CC the moment I read about it, and then engaged my brain and started thinking. There were some minor losses, but acting so fast got me out of the way of nearly all of the initial move.

I'm confident I'll react similarly in the future. Part of that confidence comes from following the company so closely and sort of gaming out my reaction to various things that I foresee that might happen. This is mostly something I do after hours, thinking about the next day. But also something I do at more of a weekly and monthly level as well.

 

[Oil4AsphaultOnly]

Funny - that's exactly what I've been thinking this morning


From my side, I need to figure out what it will take for me to be comfortable going really aggressive on the put side. The easy notion is to go back to short puts fully cash backed (the only kind ), selling ATM. And if the shares go badly enough against me then I pull out the put spread as a management technique to bring my strike price back to the share price in a quick and dramatic fashion.

Example - I cleared up those 760 puts by moving to a $200 wide put spread. 4 of those used the same margin as 1 short put (slightly more to be precise) but moved the short put strike from 760 down to 660 I think it was (maybe 640). Whatever it was, it was maybe $10 ITM and the shares went OTM that week letting me close for a 95% gain or something, and resolving those 760 strike / $140ish ITM puts in 1 week.

So put spreads enable adding leverage to a position that is going badly against, in judicial quantities and timing.


H'mm... so maybe one of the put spread management techniques is that, when needed (rare!), cut the spread size in half while doubling the number of positions (no change in margin) in order to change the short strike more dramatically. Options chain ho!

The downside with put spreads is that they're going to resolve as cash - they won't resolve into shares which is the other management technique that backs short puts in the wheel. I just discovered, much to my chagrin, that I wasn't willing to take assignment on those puts when I got so deeply ITM.


Well - whatever the answer will be, I will continue following along with what you're doing and be figuring out what if anything I'll change on my side. Working towards the best of both isn't something I need to find anytime soon - my current pattern is working well for me and is going way above what I need it to be.

An important reason to me for pursuing this optimization is what I think of as dynamic risk management. Dynamic in that I don't know where the bad stuff will come from, but if I'm collecting particularly large premiums all along the way then when the bad stuff does arrive, then I've got a bank of credits if you will, to help pay for the bad stuff. The big credits can be used on anything.

As opposed to more 'static' risk management such as selling .10 delta options. They're far OTM and safe, until they aren't. And collecting small premiums along the way, a single rare loss can wipe out months or more of earnings (ask me how I know ). There is a kind of safety in big premiums (with more frequent, and typically smaller, losses). The balance - must find the balance.


A request of any and all - if you find yourself rolling a put spread, please post about that and provide detail into your thinking - what did you choose, what alternatives did you consider, what do you think your next move will be given yet another move against. That sort of stuff.

I want to learn about put spread management in the real world as fast as I can

In exchange I'll be doing the same. So far my recent put spread management has been open today, close in 1 or 2 days for 40-80% gains. Not exactly rocket science.

I rolled my 10x BPS last week (was going on a camping trip and was worried about internet access). So I first rolled the long leg down (from 8/6 560p down to 8/13 520p for a net debit of $50 per contract), then I rolled the short leg up (from 8/6 600p up to 8/13 620p for a net credit of $180 per contract). My thoughts were that I wanted to make sure to not use any margin, since TDAmeritrade charges margin interest daily on the highest balance reached. Funny enough, despite the spread being $100 (and I only had ~$40k of cash in the account), the margin balance didn't change beyond the $500 needed to roll the long-put position. It seems the margin calculations (would love a reply if someone knows the actual formula?) isn't simply based on: # of contracts * spread-size

When they reached 80% of their profit yesterday, I rolled them again (same method, but kept the same strike prices) into next week. I usually choose ~10am PST (1pm EST) to carry out the rolls, since that's when the stock price is usually stable, so there's no worry about one leg of the put spread running away from me before I can roll the other leg.

I usually don't wait until Friday to roll, because I just don't have enough cash to take assignment, so I'm just happy to collect my pennies. ~$800 / wk of income off of $40k of cash is more than enough income for me (since I'm collecting premiums from my covered calls as well).

 

[AquaY]

I rolled my 10x BPS last week (was going on a camping trip and was worried about internet access). So I first rolled the long leg down (from 8/6 560p down to 8/13 520p for a net debit of $50 per contract), then I rolled the short leg up (from 8/6 600p up to 8/13 620p for a net credit of $180 per contract). My thoughts were that I wanted to make sure to not use any margin, since TDAmeritrade charges margin interest daily on the highest balance reached. Funny enough, despite the spread being $100 (and I only had ~$40k of cash in the account), the margin balance didn't change beyond the $500 needed to roll the long-put position. It seems the margin calculations (would love a reply if someone knows the actual formula?) isn't simply based on: # of contracts * spread-size

When they reached 80% of their profit yesterday, I rolled them again (same method, but kept the same strike prices) into next week. I usually choose ~10am PST (1pm EST) to carry out the rolls, since that's when the stock price is usually stable, so there's no worry about one leg of the put spread running away from me before I can roll the other leg.

I usually don't wait until Friday to roll, because I just don't have enough cash to take assignment, so I'm just happy to collect my pennies. ~$800 / wk of income off of $40k of cash is more than enough income for me (since I'm collecting premiums from my covered calls as well).

$800 income per week on $40,000 cash is over a 100% return.
nice

 

[Oil4AsphaultOnly]

$800 income per week on $40,000 cash is over a 100% return.
nice

Yeah, I'm pretty sure I'm not understanding the cash requirements for my margin account correctly somewhere, but as long as I'm not charged margin interest for my BPS, then I'm happy with it!

 

[Chenkers]

$800 income per week on $40,000 cash is over a 100% return.
nice

Regarding annual returns, I've done some more analysis on the table I posted a few days ago to look at what the annual returns would be if repeated weekly. The options in the table below have been calculated on the basis of using the same amount of maintenance margin, in this case $100,000. These are on the basis of a mid-week STO with the number of contracts calculated to equal a $100k increase in maintenance margin. These results are likely to be conservative since IV is currently very low and the strikes relatively safe.

Option	Number	Premium	Weekly Revenue	Margin Impact	TSLA Value	Annual Return	TSLA 30% Gain	Total Gain pa	Annual Return
IC - 650/680 740/770	31.1​	$4.50​	$13,984​	$100,000​	$150,150​	484%​	$45,045​	$772,205​	514%​
BPS - 650/680	27.9​	$1.80​	$5,017​	$100,000​	$150,150​	174%​	$45,045​	$305,946​	204%​
Put - 680	2.3​	$2.60​	$596​	$100,000​	$150,150​	21%​	$45,045​	$76,055​	51%​
CS Put - 680	1.0​	$2.60​	$260​	$43,599​	$68,000 (Cash)​	20%​	$20,400​	$33,920​	50%​
Strangle - 680 740	2.3​	$5.15​	$1,196​	$100,000​	$150,150​	41%​	$45,045​	$107,262​	71%​

For my broker IB, $100k of margin requirement equates to $150k worth of TSLA shares (212 shares, 66% margin requirement). In reality you will need additional margin to act as a buffer but I've just done the return calculation based on the actual capital used. I've included HODL share gains if TSLA goes up, say 30%. I've also added the option for a cash secured Put but the premium in this case is pretty low.

The beauty of trading like this is that you still retain your HODL shares and then sell options using their corresponding margin for much greater overall returns.

 

[Yoona]

Regarding annual returns, I've done some more analysis on the table I posted a few days ago to look at what the annual returns would be if repeated weekly. The options in the table below have been calculated on the basis of using the same amount of maintenance margin, in this case $100,000. These are on the basis of a mid-week STO with the number of contracts calculated to equal a $100k increase in maintenance margin. These results are likely to be conservative since IV is currently very low and the strikes relatively safe.

Option	Number	Premium	Weekly Revenue	Margin Impact	TSLA Value	Annual Return	TSLA 30% Gain	Total Gain pa	Annual Return
IC - 650/680 740/770	31.1​	$4.50​	$13,984​	$100,000​	$150,150​	484%​	$45,045​	$772,205​	514%​
BPS - 650/680	27.9​	$1.80​	$5,017​	$100,000​	$150,150​	174%​	$45,045​	$305,946​	204%​
Put - 680	2.3​	$2.60​	$596​	$100,000​	$150,150​	21%​	$45,045​	$76,055​	51%​
CS Put - 680	1.0​	$2.60​	$260​	$43,599​	$68,000 (Cash)​	20%​	$20,400​	$33,920​	50%​
Strangle - 680 740	2.3​	$5.15​	$1,196​	$100,000​	$150,150​	41%​	$45,045​	$107,262​	71%​

For my broker IB, $100k of margin requirement equates to $150k worth of TSLA shares (212 shares, 66% margin requirement). In reality you will need additional margin to act as a buffer but I've just done the return calculation based on the actual capital used. I've included HODL share gains if TSLA goes up, say 30%. I've also added the option for a cash secured Put but the premium in this case is pretty low.

The beauty of trading like this is that you still retain your HODL shares and then sell options using their corresponding margin for much greater overall returns.

i love this data analysis!

 

[stealthyc]

Regarding annual returns, I've done some more analysis on the table I posted a few days ago to look at what the annual returns would be if repeated weekly. The options in the table below have been calculated on the basis of using the same amount of maintenance margin, in this case $100,000. These are on the basis of a mid-week STO with the number of contracts calculated to equal a $100k increase in maintenance margin. These results are likely to be conservative since IV is currently very low and the strikes relatively safe.

Option	Number	Premium	Weekly Revenue	Margin Impact	TSLA Value	Annual Return	TSLA 30% Gain	Total Gain pa	Annual Return
IC - 650/680 740/770	31.1​	$4.50​	$13,984​	$100,000​	$150,150​	484%​	$45,045​	$772,205​	514%​
BPS - 650/680	27.9​	$1.80​	$5,017​	$100,000​	$150,150​	174%​	$45,045​	$305,946​	204%​
Put - 680	2.3​	$2.60​	$596​	$100,000​	$150,150​	21%​	$45,045​	$76,055​	51%​
CS Put - 680	1.0​	$2.60​	$260​	$43,599​	$68,000 (Cash)​	20%​	$20,400​	$33,920​	50%​
Strangle - 680 740	2.3​	$5.15​	$1,196​	$100,000​	$150,150​	41%​	$45,045​	$107,262​	71%​

For my broker IB, $100k of margin requirement equates to $150k worth of TSLA shares (212 shares, 66% margin requirement). In reality you will need additional margin to act as a buffer but I've just done the return calculation based on the actual capital used. I've included HODL share gains if TSLA goes up, say 30%. I've also added the option for a cash secured Put but the premium in this case is pretty low.

The beauty of trading like this is that you still retain your HODL shares and then sell options using their corresponding margin for much greater overall returns.

I would be interested to see a couple loss columns as well to get a better sense of the risk involved for each. For instance, there could be a max loss column, though that would not really be realistic for a weekly put, but something like loss @ 20% price movement against, and loss @ 10% price movement against would be interesting. Like at those strikes, with 2.3 Puts which are using 100k margin, if price drops 10% from 710 you are looking at an 8k loss, but the BPS are going to be 78k loss.

 

[Drezil]

Regarding annual returns, I've done some more analysis on the table I posted a few days ago to look at what the annual returns would be if repeated weekly. The options in the table below have been calculated on the basis of using the same amount of maintenance margin, in this case $100,000. These are on the basis of a mid-week STO with the number of contracts calculated to equal a $100k increase in maintenance margin. These results are likely to be conservative since IV is currently very low and the strikes relatively safe.

Option	Number	Premium	Weekly Revenue	Margin Impact	TSLA Value	Annual Return	TSLA 30% Gain	Total Gain pa	Annual Return
IC - 650/680 740/770	31.1​	$4.50​	$13,984​	$100,000​	$150,150​	484%​	$45,045​	$772,205​	514%​
BPS - 650/680	27.9​	$1.80​	$5,017​	$100,000​	$150,150​	174%​	$45,045​	$305,946​	204%​
Put - 680	2.3​	$2.60​	$596​	$100,000​	$150,150​	21%​	$45,045​	$76,055​	51%​
CS Put - 680	1.0​	$2.60​	$260​	$43,599​	$68,000 (Cash)​	20%​	$20,400​	$33,920​	50%​
Strangle - 680 740	2.3​	$5.15​	$1,196​	$100,000​	$150,150​	41%​	$45,045​	$107,262​	71%​

For my broker IB, $100k of margin requirement equates to $150k worth of TSLA shares (212 shares, 66% margin requirement). In reality you will need additional margin to act as a buffer but I've just done the return calculation based on the actual capital used. I've included HODL share gains if TSLA goes up, say 30%. I've also added the option for a cash secured Put but the premium in this case is pretty low.

The beauty of trading like this is that you still retain your HODL shares and then sell options using their corresponding margin for much greater overall returns.

On question on the IC: If TSLA rises 30% (3rd last colums) shouldn't the IC cause max-loss? because with an SP 30% higher you should be way above 770.

 

[stealthyc]

On question on the IC: If TSLA rises 30% (3rd last colums) shouldn't the IC cause max-loss? because with an SP 30% higher you should be way above 770.

I believe he means 30% gain over a year not in one week.

 

[Chenkers]

On question on the IC: If TSLA rises 30% (3rd last colums) shouldn't the IC cause max-loss? because with an SP 30% higher you should be way above 770.

The 30% is over a year. ie if you hold the 212 shares and the stock rises 30% over a year, what are the overall gains of stock plus weekly options trading.

 

[ReddyLeaf]

Hey guys-

This week I started day trading TSLA covered calls. Following the discussion above, the premiums these days are too low for my liking considering the potential for a gap up any day now.

I am selling cc’s into rapid price rises and buying back on the reversal.

today’s trades - all the same contract:
STO $740c 8/20 for $6.10 @9:32 AM
BTC for $5.10 @9:37 AM

STO for $5.50
BTC for $4.60

STO for $4.60
BTC for $4.50

So I made $2.00 per share on these trades today.

glta

This sounds like leveraged day trading. Definitely not for everyone. Last Friday, I bought some 8/13 +c720s and sold them Monday just for a bit of fun. Made a small amount, but it’s more stress than it’s worth.

 

[Cherry Wine]

STO 30x $750c 8/13 @ .98.

 

[adiggs]

I'm so smart! (lucky)

I closed my 740 and 750 calls for 8/20 this morning when the shares were still flat - roughly a 60% gain on those. Now the share price has shot up and I could sell those same positions for the same price as I sold them for originally.


So I'm down to BPS below 700 and seeing what develops. I'll reopen the CC on a pop upward. That might mean later today.

 

[Chenkers]

I would be interested to see a couple loss columns as well to get a better sense of the risk involved for each. For instance, there could be a max loss column, though that would not really be realistic for a weekly put, but something like loss @ 20% price movement against, and loss @ 10% price movement against would be interesting. Like at those strikes, with 2.3 Puts which are using 100k margin, if price drops 10% from 710 you are looking at an 8k loss, but the BPS are going to be 78k loss.

Here you go:

Option	Number	Premium	Revenue	-10% Max Loss	-20% Max Loss
IC - 650/680 740/770	31.1​	$4.50​	$13,984​	-$89,838​	-$89,838​
BPS - 650/680	27.9​	$1.80​	$5,017​	-$82,953​	-$82,953​
Put - 680	2.3​	$2.60​	$596​	-$7,973​	-$24,306​
Put - 680 Cash Secured	1.0​	$2.60​	$260​	-$3,476​	-$10,597​
Strangle - 680 740	2.3​	$5.15​	$1,196​	-$7,935​	-$24,478​

With the spreads the lower bought put caps the max loss, while with the straight puts there's no cap. You are right that the max loss relative to margin is higher with the spreads. However the max loss relative to the premium collected is a much higher ratio for the puts and strangle. I don't see these positions as high risk as I would almost never actually take the loss if I have sufficient spare margin buffer. The spreads, calls or puts can always be rolled if they go ITM or with sufficient margin buffer can be split or flipped from put to call etc to close out the option and still capture the original premium (or more). Plus if a loss is a rare event you can make more than enough premium with the higher returning options over time to cover an occasional loss.

 

[MaxPain]

Regarding annual returns, I've done some more analysis on the table I posted a few days ago to look at what the annual returns would be if repeated weekly. The options in the table below have been calculated on the basis of using the same amount of maintenance margin, in this case $100,000. These are on the basis of a mid-week STO with the number of contracts calculated to equal a $100k increase in maintenance margin. These results are likely to be conservative since IV is currently very low and the strikes relatively safe.

Option	Number	Premium	Weekly Revenue	Margin Impact	TSLA Value	Annual Return	TSLA 30% Gain	Total Gain pa	Annual Return
IC - 650/680 740/770	31.1​	$4.50​	$13,984​	$100,000​	$150,150​	484%​	$45,045​	$772,205​	514%​
BPS - 650/680	27.9​	$1.80​	$5,017​	$100,000​	$150,150​	174%​	$45,045​	$305,946​	204%​
Put - 680	2.3​	$2.60​	$596​	$100,000​	$150,150​	21%​	$45,045​	$76,055​	51%​
CS Put - 680	1.0​	$2.60​	$260​	$43,599​	$68,000 (Cash)​	20%​	$20,400​	$33,920​	50%​
Strangle - 680 740	2.3​	$5.15​	$1,196​	$100,000​	$150,150​	41%​	$45,045​	$107,262​	71%​

For my broker IB, $100k of margin requirement equates to $150k worth of TSLA shares (212 shares, 66% margin requirement). In reality you will need additional margin to act as a buffer but I've just done the return calculation based on the actual capital used. I've included HODL share gains if TSLA goes up, say 30%. I've also added the option for a cash secured Put but the premium in this case is pretty low.

The beauty of trading like this is that you still retain your HODL shares and then sell options using their corresponding margin for much greater overall returns.

This is probably a dumb question, but what is the formula for calculating margin impact?

 

[stealthyc]

Here you go:

Option	Number	Premium	Revenue	-10% Max Loss	-20% Max Loss
IC - 650/680 740/770	31.1​	$4.50​	$13,984​	-$89,838​	-$89,838​
BPS - 650/680	27.9​	$1.80​	$5,017​	-$82,953​	-$82,953​
Put - 680	2.3​	$2.60​	$596​	-$7,973​	-$24,306​
Put - 680 Cash Secured	1.0​	$2.60​	$260​	-$3,476​	-$10,597​
Strangle - 680 740	2.3​	$5.15​	$1,196​	-$7,935​	-$24,478​

With the spreads the lower bought put caps the max loss, while with the straight puts there's no cap. You are right that the max loss relative to margin is higher with the spreads. However the max loss relative to the premium collected is a much higher ratio for the puts and strangle. I don't see these positions as high risk as I would almost never actually take the loss if I have sufficient spare margin buffer. The spreads, calls or puts can always be rolled if they go ITM or with sufficient margin buffer can be split or flipped from put to call etc to close out the option and still capture the original premium (or more). Plus if a loss is a rare event you can make more than enough premium with the higher returning options over time to cover an occasional loss.

Thanks for the update. Max loss relative to premium is higher of course for a put, but that is why different percentages matter, because actual max loss for a put is not going to happen. In the 10% case, the ratio of loss to revenue is still a bit worse with the BPS than with the Put. I'm not trying to advise one way or the other, I'm mostly just curious. I'm not terribly afraid of going ITM, i've been through it with puts plenty of times. It's more just risk/reward that I'm trying to establish. Tesla stock can easily move 10% in a week. Low IV is not really predictive, as IV is calculated only based on existing prices. Personally I may try out some BPS, but I'm too bullish for IC's. Margin calculations seem to vary as well as I can sell 4 of those puts for next week for 100k margin. Interesting info though!

 

[Chenkers]

This is probably a dumb question, but what is the formula for calculating margin impact?

The calculations I've used here are more specific to having IB as the broker and using their portfolio margin. These were all calculated using the IB performance profile for each option. Another broker will have a different margin calculation, whether rules based or portfolio/risk based and so the results will vary.