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Options library / Level 2 Structure / Strategy 09

Bear call spread for UK investors: the credit vertical that caps a naked call

The same “this will not rise” view as an uncovered short call, with one bought wing that converts an unlimited loss into width minus credit — and, because the requirement falls further than the premium does, a better return on capital.

L2Margin account mandatory
£44.40Net credit on one ICE contract
£155.60Maximum loss, fixed by the wing
IVR ≥ 30The entry gate for this structure
Options hub Level 2 gate Bear call spread Uncovered short call Greeks and IV Assignment and expiry UK tax and platforms Position sizing
09

Bear Call Spread

Sell a call, buy a cheaper one above it — the naked call's view with the tail bought back for £60.70
L2 · StructureBearish to neutralDefined risk — by construction£200 per ICE contract

Prerequisite strategies: you must have traded the covered call with real money, so that you have granted a call and had it assigned, and the long call, so that you have owned one. Clear the Level 2 gate first — it needs a margin account, spread permission and a live IV rank source. Next: the bull put spread, this structure's mirror below the market, and then the iron condor, which is the two of them at once.

Why this structure exists

There is exactly one way to be paid for believing a share will not rise, and it is to grant somebody a call. Level 1 lets you do that only when you already own the shares, because the shares are the collateral. Take them away and you have the uncovered short call: same view, same premium, and a loss with no upper bound, because a share price has no ceiling and no amount of cash can stand behind that promise.

The bear call spread is what happens when you buy the ceiling instead of owning the shares. Grant the 560 call, buy the 580 above it, and the worst case stops being a function of how far BP goes and becomes one number you chose at entry: width minus credit. Twenty pence of width, 4.44p of credit, 15.56p of loss — £155.60 per 1,000-share ICE contract, whether BP finishes at 581p or is bid for at 742p. That is risk defined by construction rather than by collateral, and on the call side it is the only definition available at all.

Why not just sell the naked call instead? Because the wing is cheap in the only currency that matters. It costs £60.70 of premium and 5.79p of breakeven cushion; it returns £665.10 of the broker's requirement, deletes an unbounded tail and removes the account level at which you are liquidated. And because the requirement falls further than the credit does, the best-case return on the capital actually tied up rises — 24.9% over 60 days against 13.5%. The wing is not insurance you pay for. It is the cheaper trade.

Construction

LegBuy / SellQuantityStrike ruleExpiry ruleTarget deltaPrice
Call (lower)SELL (credit)1 contract = 1,000 shares (ICE UK); 100 (US)First listed strike at 0.25–0.35 delta, and at least +0.5 SD above spot30–60 DTE; never a weekly+0.3110.51p = £105.10
Call (upper)BUY (debit)1 contract, same expiryThe strike that makes width − credit fit your 2% risk capIdentical expiry — never a different one+0.206.07p = −£60.70
NETNet credit1 vertical, 20p wide560 / 580, BP modelled at 530p16 October 2026, 60 days−0.106 per share4.44p = £44.40

Same underlying, same expiry, same size, higher strike bought: break any of those four and it is not a vertical, it is a granted call the broker margins on its own. Four inequalities before the order goes in:

  • Credit ≥ 20% of the width — not the 25% you use on the put side. 4.44p of 20p is 22.2%. At the same 0.31 short delta a put spread on this chain pays 28.2%, so importing the put-side rule quietly drags your short call nearer the money.
  • (Width − credit) × contract size × contracts ≤ 2% of the account. £155.60 is 2% of £7,780, so three contracts suit a £25,000 book.
  • Short strike at least +0.5 SD above spot. One SD over 60 days at 26% volatility is 55.87p, so 560p is +0.54 SD and the 580 wing +0.89 SD. The naked seller must go beyond +1 SD; the wing is what lets you sell the closer, richer strike.
  • Round-trip commission ≤ 15% of the credit. £5.60 against £44.40 is 12.6%. Fail it and the answer is a wider spread, never more contracts.
Net credit
£44.40
Max loss
£155.60
Max profit
£44.40
Breakeven
564.44p
Buying power
£200 held
Risk type
Defined by construction

Formulas for any call credit vertical: max profit = net credit × contract size, £38.80 after the £5.60 round trip. Max loss = (width − net credit) × contract size, £161.20 closed in the market. Breakeven = short strike + net credit = 564.44p, or 563.88p with costs. Buying power = width × contract size, and the credit is already in your cash, so new capital consumed is £155.60. Modelled at entry: 74.9% chance of finishing below breakeven, 72.5% of keeping the whole credit, 17.6% of the full loss.

Payoff — short BP 560 call / long BP 580 call, £ P&L per 1,000-share contract
£ P&L per contract (1,000 shares) BP share price at expiry (pence) +£44.40 £0 −£50 −£100 −£155.60 500p 520p 540p 560p 580p 600p 620p BP today 530p +1 SD 585.9p Short 560p Long 580p BE 564.44p Uncovered: −£494.90 at 620p, and no floor below Value today, 60 DTE Max profit +£44.40 at expiry Max loss −£155.60

Everything happens in 20p of BP: from keeping every penny at 560p to losing every penny at 580p is 3.8% of the share price, and a cash bid crosses it before the market opens. The purple line is the position today — below the payoff on the left, because a credit is only earned with time, and above the floor on the right, because the wing still has value. The red dotted line is the same 560 call sold uncovered: it leaves the top of the chart at 566p, exits the bottom at 589p and never turns back. The gap between it and the flat red plateau is what £60.70 bought.

Entry criteria

GateRuleReason
IV rank / IV percentileIVR ≥ 30 to sell this; below 25 buy a bear put spread insteadYou are short £1.48 of vega a point. The same 560/580 strikes pay £28.99 at 18% implied volatility and £56.99 at 38%. The premium is the only thing you are being paid
Credit vs widthCredit ≥ 20% of the width, short leg at 0.35 delta or lowerNot the put-side 25%. At a matched 0.31 short delta this chain pays 28.2% on the put side and 22.2% on the call side, so the put-side rule quietly drags your short call nearer the money
Days to expiry30–60 at entry, closed at 21Net gamma at a tested short strike runs −0.00030 at 60 DTE to −0.02991 at 2 DTE. The last three weeks are unpaid risk
StrikesShort at 0.25–0.35 delta and at least +0.5 SD out; long at the width that fits your 2% capDelta picks the odds, width picks the loss. Two decisions, and beginners fuse them
LiquidityBid-ask ≤ 10% of mid on each leg; open interest ≥ 100 on both10% on both ICE legs is £16.58 round-trip — 37.3% of the credit. Most ICE UK single-stock series fail this
Underlying and skewA large FTSE 100 name with no plausible bidder — no stale offer speculation, not persistently below book, not the obvious target in a consolidating sector — and whose 25-delta call is not bid relative to the 25-delta putA cash bid takes a call spread to its maximum in one print and pins the price there: the one event the wing sizes but cannot avoid. An upside-bid skew is the market pricing that exact tail
Event calendarNo results, trading statement, index review or ex-dividend date inside the windowA short call whose extrinsic value falls below the coming dividend should be assumed assigned — a calendar event, not a price event

Do not enter if: IV rank is below 30 — selling cheap calls removes the only edge the trade has, and the answer is a debit spread or no trade; the credit is under 20% of the width; the max loss at your size exceeds 2% of the account; the underlying has been the subject of any bid speculation, however stale; you hold a cash account, because no amount of cash secures a granted call; or results fall inside the window.

What the wing costs, and what it buys

Three ways to express the identical view — BP does not reach 560p by 16 October — on the identical short call, differing only in whether you buy a ceiling and where you put it.

 Uncovered short 560 call560 / 580 spread — this page560 / 600 spread
The wing, and what it costsNot bought — that is the trade580 call, £60.70 = 57.8% of the gross credit600 call, £33.20 = 31.6%
Net credit£105.10£44.40£71.90
Breakeven570.23p (BP +7.59%)564.44p (BP +6.50%)567.19p (BP +7.02%)
Maximum lossUNLIMITED£155.60£328.10
Requirement at entry / new buying power£865.10 / £760.00£200.00 / £155.60£400.00 / £328.10
Best case ÷ capital used, 60 days13.5%24.9%20.2%
Loss on a 40% cash bid (BP 742p)−£1,717.70−£161.20−£333.70
Requirement that morning£3,304.00£200.00, unchanged£400.00, unchanged
Equity needed to survive it£5,021.70The loss, and nothing elseThe loss, and nothing else

The wing costs £60.70 and 5.79p of cushion. It returns £665.10 of requirement on day one, £1,556.50 on the one morning that matters, and the whole concept of a liquidation level. Read the sixth row twice: the requirement falls by 76.9% while the credit falls by 57.8%, so the defined-risk version earns 1.85 times the return on capital of the naked one in its best case. Paying for the ceiling is not a tax on the trade; not paying for it is.

The uncovered short call page sets one test for selling naked instead: the capping call must cost more than half the credit. The 580 wing costs 57.8%, so it fails — and the answer is to move the wing, not remove it. The 600 wing costs 31.6%, passes, and still caps the worst case at £328.10 against no cap at all. That is the whole reply to “the hedge is too expensive”: buy a cheaper hedge.

Credit or debit: the same view, two structures

A bear call spread and a bear put spread are one opinion — this share falls, or at least does not rise — from opposite sides of the premium, and IV rank picks between them. Modelled on the same BP chain so the comparison is like for like:

 Bear call spread (credit) — this pageBear put spread (debit)
Legs on BP at 530p, 60 DTESell 560 call 10.51p, buy 580 call 6.07pBuy 510 put 13.62p, sell 490 put 7.32p
Cash at entryReceive £44.40Pay £63.00
Max profit / max loss£44.40 / £155.60£137.00 / £63.00
Breakeven564.44p — BP may rise 6.50%503.70p — BP must fall 4.96%
Net vega−£1.48 a point+£1.57 a point
Buying power used£155.60 (width − credit)£63.00 (the debit)
Use it whenIV rank 30 and aboveIV rank below 25
Day-one taxable gain£105.10 (short 560 call granted) — 237% of the net credit£73.20 (short 490 put granted), on a trade that cost you money

The credit version pays you for not being wrong, which is why its probability is better and its payoff ratio worse; the debit version pays you for being right. The vega row is the decision rule in one line: at IV rank 30 and above be the seller of expensive volatility, below 25 the buyer of cheap volatility, same direction either way. The last row is the one nobody tells you — the credit structure books a day-one chargeable gain more than twice the cash it received, because HMRC taxes the leg you granted and ignores the leg you bought until it closes.

And call-versus-put is not the real choice at all. Build the bear put spread at the identical 560/580 strikes and it costs 15.43p against this page's 4.44p credit; the two sum to 19.87p, exactly 20p of width discounted at 4% over 60 days. The gap is interest and nothing else. What you are really choosing is which side of the money your short strike sits.

Greeks at entry and how they evolve

Greek (net, per contract)Entry: 60 DTE, 530p30 DTE, unchanged7 DTE, unchanged+1 SD (585.9p, IV 28%)−1 SD (474.1p, IV 25%)
Delta (per share)−0.106 (short 106 shares)−0.119−0.058−0.161−0.008
Gamma−0.00123−0.00281−0.00566+0.00125−0.00059
Theta (£ per day)+£0.29+£0.70+£1.46−£0.51+£0.11
Vega (£ per vol point)−£1.48−£1.69−£0.79+£0.99−£0.27
Position mark£44.39£30.73£4.89£122.16£0.94

Black–Scholes at 26% implied volatility unless stated, 4% rates and a 5.4% dividend yield, per one 1,000-share contract — the same inputs that price the uncovered short call page's 580 call at 6.07p, which is the wing bought here. The adverse column steps volatility up, because on a single stock it is the upside that carries the event risk a short call is selling. One standard deviation over 60 days is 55.87p.

Vega decides whether this trade should exist; gamma decides what being wrong costs. Read the +1 SD column twice. At 585.9p the position has gone through the long strike and every Greek has changed sign: gamma positive, vega positive, theta negative £0.51 a day. You are no longer renting out time, you are paying for it, and you now need volatility to fall and BP to retreat before expiry. The mark is £122.16 against a £44.40 credit — exactly 50.0% of the maximum loss, gone. That is the character flip, and it happens at the long strike rather than at any level you were watching.

Before it, this is a slow theta business earning 29 pence a day against £155.60 of exposure, rising to £1.46 by 7 DTE. Run the same clock at the short strike, though, and net gamma goes from −0.00030 at 60 DTE to −0.00735 at 7 DTE: a further 3% rise from 560p costs £21.94 with 60 days left and £61.06 with seven. Holding to expiry is a gamma decision, not a patience one.

UK worked example — ICE Futures Europe, 1,000 shares per contract, physically delivered

BP p.l.c. modelled at 530p, and you need it not to rise more than 6.5%

The ICE Futures Europe BP option is quoted in pence per share; one contract confers rights over 1,000 shares; it is American style, so it can be exercised against you on any business day; it is physically delivered; the tick is 0.25p (£2.50); and the October series stops trading at 16:30 London on Friday 16 October 2026. One penny of option price is £10 of contract value. Entered 60 days out, on 17 August 2026, at an IV rank of 38 — clear of the 30 gate.

The trade, placed as a single spread order: sell 1 × BP October 2026 560 call at 10.51p, buy 1 × BP October 2026 580 call at 6.07p.

Short 560 call granted (delta +0.31):10.51p × 1,000 = +£105.10
Long 580 call bought (delta +0.20):6.07p × 1,000 = −£60.70
Net credit:4.44p = £44.40 — 22.2% of the width
Commission (IBKR UK £1.00 + £0.37 exchange + £0.03 clearing per leg):−£2.80 to open, −£2.80 to close
Spread width, and what the broker holds:20p × 1,000 = £200.00
Breakeven (560 + 4.44):564.44p — BP may rise 6.50%
Modelled probability of profit:74.9%; of the full credit, 72.5%
MAX PROFIT = credit − round-trip commission:£38.80 — 24.9% of the capital used, over 60 days
MAX LOSS = width − credit:15.56p = £155.60 (£161.20 closed at market)

Branch A — the target fires. BP 522p on 16 September 2026, 30 days left. A 1.5% drift down has done the work; the spread marks 2.22p.

Buy the spread back:2.22p × 1,000 = £22.20
Profit:+£16.60 after both commissions — 50.0% of the credit gross
ACTION:The 50%-of-credit target fired at 522.1p. Close both legs as one order.

Branch B — the short strike is tested. BP 560p on 16 September 2026, 30 days left, IV up to 30%.

Spread now marks:7.92p = £79.24 (short 18.82p, long 10.89p)
Unrealised loss:−£34.84 — 22.4% of the max loss; net delta −0.159, or 159 BP shares short
The only legal roll:Out in time, same strikes. November 560/580 fills at 8.19p against the 7.92p to close — a net £2.63 credit
ACTION:The strike is breached on the close. Take −£40.44 and go. Rolling up and out to November 580/600 fills at 6.17p against 7.92p — a £17.51 debit. Forbidden.

Branch C — assigned early, and not because of the price. BP 585p on 7 October 2026, 9 days left, with an ex-dividend date the next morning. The short 560 call is worth 26.50p, of which 25.00p is intrinsic and 1.50p is extrinsic. The modelled 5.4% yield is about 7.2p a quarter, so a holder captures 7.2p by discarding 1.5p. Somebody will, and you find out at breakfast.

Assigned: deliver 1,000 BP at 560p:+£5,600.00 — and you own no shares
Buy 1,000 BP in the market at 585p to settle it:−£5,850.00
SDRT at 0.5% on your own acquisition:−£29.25
Sell — do not exercise — the long 580 call at 12.07p:+£120.65
Plus the original credit, less all commissions (£2.80 + £1.40 + £3.00):+£44.40 − £7.20
NET:−£121.40 — better than max loss, because the long call still held £70.65 of time value

Exercising that long 580 call instead, to “keep it simple”, buys the shares at 580p and gives the £70.65 away to save 25p of stamp duty: −£187.40, or £66.00 worse. If you cannot cover before the record date you also owe the lender the manufactured dividend, roughly £71.55, taking it to −£192.95 — the exact sum the exercising holder was reaching for. Overnight, a £200 requirement became a £5,850 share purchase.

Branch D — held to the last trading day, BP at 585p. Both legs finish in the money, so the spread is worth its full 20p width either way; the only question is how you pay for it.

Closing in the market (spread at 20p):£44.40 − £200.00 − £5.60 = −£161.20
Letting it deliver — assigned on the 560:+£5,600.00
— exercising the 580 to source the shares:−£5,800.00
— SDRT at 0.5% of the £5,800 consideration:−£29.00 (the holder exercising against you pays SDRT on the £5,600)
— plus the original credit, less the opening commission:+£44.40 − £2.80
Delivery net, before exercise and assignment fees:−£187.40 — £26.20 worse, and £5,800 of cash overnight

On a US underlying instead — 100 shares a contract, deeper chains, the route most UK readers take — the gain is computed in sterling at the spot rate on each disposal date, so the two currency legs are struck on different days. A $110 credit on a $5-wide spread, the same 22% of width as the UK trade, fixes £81.17 of grant proceeds at GBP/USD 1.3552 the day you sell. Buy it back for $380 with the rate at 1.2900 and it costs £294.57, against the £280.40 an unchanged rate would have given: a £213.40 sterling loss on a $270 dollar loss. FX added £14.17, and the conversion spread lands on top, twice.

This is a single, hand-picked, favourable scenario. It is not a typical or expected outcome. Every premium is modelled from Black–Scholes at the stated inputs rather than taken from a live chain; 530p is illustrative and real listed strikes and quotes will differ, with ICE UK series materially wider. Under the model that prices it a credit spread has no edge at all — the only edge on offer is that implied volatility exceeds the volatility that follows, which is what the IV rank gate is trying to buy. Past performance, including any illustrative example shown here, is not a reliable indicator of future results.

Management and adjustment

TriggerDiagnosisActionDo NOT do this
Short strike touched intraday, then breached on the closeA touch is noise; a close is the thesis being wrong rather than earlyNothing on the touch — judge it on the close. On the close, CLOSE: −£40.44 at 30 DTE against a £155.60 max lossAdjust on a wick, or wait for the pullback. Short strike to full loss is 20p — 3.6% above 560p, one headline
You want more timeDefensible only if the arithmetic permits, and only two rolls existRoll out at the same strikes: November 560/580 for a net £2.63 creditRoll up and out (November 580/600 is a £17.51 debit), or widen for a credit (November 560/600 pays £64.36 and takes the worst case to £291.24). Both are new risk wearing the word “defence”
IV expands, then collapses, after entryA −£1.48-a-point vega loss is not yet a delta loss; a vega gain is the thesis paying earlyHold while BP is below the short strike and the stop is intact. On the collapse, take the 2.22p target the day it appearsPanic-close on the vega mark, or hold past the target for £0.29 a day against £155.60 of exposure
Short call ITM, extrinsic value below the next dividendEarly exercise has turned rational for the holder — the call side's signature failure, and a calendar event rather than a price oneCLOSE the whole spread the business day before the ex-dateAssume assignment only happens at expiry. ICE BP is American style, exercisable on any business day
Assigned early on the short 560You are short 1,000 shares you never owned; the long 580 still covers the obligationBuy the shares in the market and sell the long call: −£121.40Exercise the long 580 to source them. That throws away £70.65 of time value to save 25p of stamp duty — £66.00 worse
A bid or offer period is announcedUndefendable. The distribution you priced no longer exists and a firm cash bid pins the share above your long strikeCLOSE at the open, and take comfort only in the number: −£161.20 and not a penny moreWait for the bid to be rejected. Rejected bids are often followed by higher ones
Results appear inside the windowShort gamma into a gap you were not paid forCLOSE before the printHold “because it is defined risk”. The definition is £155.60 and a gap reaches it in a session

ROLL WHEN BP is at or just above the short strike, more than 21 days remain, and the order fills for a net credit at the same strikes and the same width. ROLL TO the next monthly expiry, one decision at a time — never strike and duration in the same order, or you will not know which one worked. DO NOT ROLL a credit spread for a net debit, ever, and do not manufacture a credit by widening: £64.36 that turns £155.60 into £291.24 is a second trade you never sized.

THE CORRECT ACTION IS TO CLOSE, NOT ROLL, when the short strike closes in the money, when BP gapped rather than drifted, when any bid or offer period is announced, when the short leg's extrinsic value drops below the coming dividend, when the 21-day time stop arrives, or when the only roll available fails a test above. Defence on a vertical has a budget, and here it is the £44.40 you were paid.

Exit rules

  • Profit target: buy the spread back at 2.22p or better — 50% of the credit — for +£22.20 gross, +£16.60 net, reached around BP 522p with 30 days left. Note what it is not: a time target. With BP unchanged at 530p the spread still marks £23.18 at 21 DTE, only 47.8% of the credit captured — time alone gets you almost to the target and not past it.
  • Stop: primary and mechanical — close on the first daily close above the 560 short strike, about −£34.84 at 30 DTE with IV at 30%, 22.4% of the max loss. Backstop: a mark-to-market loss of 1× the credit (£44.40, the spread at 8.88p, around BP 566p at 30 DTE). Do not import the 2× convention from undefined-risk premium selling — 2× the credit is £88.80, 57.1% of the maximum loss, and a stop that fires after most of the damage is not a stop.
  • Time stop: close at 21 DTE regardless of P&L — Friday 25 September 2026. The last three weeks pay the most theta and charge the most gamma, and on a £44.40 credit that is not a trade worth making.
  • Assignment-avoidance exit: close the day the short leg's extrinsic value drops below the coming dividend — on the modelled 5.4% yield, roughly 7.2p a quarter — and be flat before 16:30 London on Friday 16 October 2026, when the ICE October series stops trading. An unclosed in-the-money spread is delivered, and delivery costs £29.00 of stamp duty, £5,800 of overnight cash and £26.20 more than closing.

If all four are silent, do nothing and check the close tomorrow. Doing nothing earns £0.29.

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UK tax and wrapper treatmentThe gap between what you banked and what HMRC taxes is wider here than on any other Level 2 structure, and nothing on the ticket tells you. Granting an option is a disposal. TCGA 1992 s.144(1) treats the grant as the disposal of an asset, and HMRC CG55536 states that the premium is a gain arising when the option is written. So HMRC never sees your £44.40 credit. It sees £105.10 of proceeds on day one, and the £60.70 you paid for the 580 call is not deductible until that option closes or lapses — a traded option that lapses being a disposal by the s.144(4) exception to the abandonment rule (CG12340). Sell this spread in March, let the wing lapse in April, and £105.10 is a 2026/27 gain while £60.70 is a 2027/28 loss that cannot be carried back: £25.22 of CGT at 24% instead of £10.66, £14.57 extra — 32.8% of the credit you actually kept. Same trade, wrong side of 5 April. If you are assigned, s.144(2) merges the grant with the delivery, so the £105.10 is added to your disposal proceeds on the 1,000 shares; exercising your own 580 call is merged with the share purchase by s.144(3), so its cost joins the base cost, and that acquisition carries SDRT at 0.5% of the consideration — £29.00 on £5,800 (STSM113030) — while the holder exercising against you pays SDRT on the £5,600. An assignment in a later tax year therefore reopens the year in which you booked the grant. A cash-settled FTSE 100 index spread carries no SDRT and cannot be assigned at all. Options of the same series pool into a s.104 holding. There is no holding-period test: 18% or 24% turns only on your unused basic-rate band in the year of disposal, above the £3,000 annual exempt amount, so £38.80 of maximum profit costs £0, £6.98 or £9.31. Wrapper: GIA only. HMRC's guidance for ISA managers lists "futures or share options" among the things qualifying shares do not include, so no spread sits in a stocks and shares ISA and no broker workaround exists; a SIPP only where the administrator permits it, which for anything with a short leg is close to unheard of. Count per cycle: two disposal computations, the first dated the day you granted the 560 call — four if it reaches delivery.

Margin and broker reality

A cash account cannot hold this trade, and on the call side there is no fallback of any kind. A short put can be secured with cash — £5,600 covers a 560 put absolutely. No amount of cash secures a short call, because there is no price at which the obligation stops growing; only the shares themselves cover it, and that is a covered call, not a spread. Cboe's strategy-based margin rules allow limited-risk spreads in a cash account only where every leg is a European-style, cash-settled index option expiring together — which an American-style, physically-delivered ICE BP option is not — and Interactive Brokers permits only limited purchase and sale of options in a Cash account, so the order is rejected in the preview rather than at the exchange. You need a margin account with spread permission, for which IBKR's published minimum is USD 2,000 or equivalent, granted through the broker's appropriateness assessment — not the US "Level 1 to 4" ladder quoted all over the internet. Hargreaves Lansdown, AJ Bell and Trading 212 offer no options at all, so this is an Interactive Brokers or Saxo trade; tastytrade is a US entity whose client assets sit under SIPC, not the FSCS.

What you do not need is uncovered-option permission. Because the long call's strike is higher, at the same expiry and size, it fully covers the short: under FINRA Rule 4210(f)(2) the long leg is paid for in full and the short leg's requirement is capped at the spread's maximum loss, so the broker holds the width, £200.00, against which your credit is already in cash. New buying power: £155.60 — and unlike the naked version it does not move with the market. The uncovered 560 call starts at £865.10 and reaches £3,304.00 on a bid; this position is £200.00 in every one of those states. IBKR margins ICE series on a risk-based house model, so your order preview governs the figure; the width is the ceiling either way. Enter and exit as a single spread order: legging in leaves you briefly holding a naked short call, the one moment this page's argument stops applying.

Two things still remove the definition. Early assignment turns £155.60 of defined risk into a £5,850 stock transaction overnight, as Branch C shows. And liquidity is a margin-equivalent cost: a 10% bid-ask on each leg is £16.58 round-trip against £5.60 of commission — 37.3% of the credit before the trade has done anything. On a thin ICE series that alone is often reason enough to run the structure on the FTSE 100 index instead: £10 an index point, cash settled at the EDSP, European exercise so early assignment cannot happen, no SDRT, and a 50-point-wide call spread is £500 of width. The trade-off is the timetable — 08:00–16:50 London, with the expiring series stopping shortly after 10:15 on the third Friday.

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The biggest bear call spread mistakeSelling it on a company somebody might buy. Every other risk on this page is a number; this one is a mechanism the wing sizes but cannot avoid. A cash offer arrives before the market opens at a 30–50% premium and three things happen at once: the share jumps clean through both strikes, implied volatility collapses so the options become almost pure intrinsic, and the price then pins near the offer until the deal completes. No path back, no reason to wait. Your defined loss is not merely reached, it is guaranteed, in one print, from a distance the chain priced at 17.6% over 60 days. One maximum loss of £161.20 takes 4.16 maximum wins at £38.80 to repay, and you will not get 4.16 of them before the next bid in that sector. The hard rule, no exceptions: never sell a call spread on a plausible target — subscale, persistently below book, the obvious consolidation candidate, or the subject of any bid speculation however stale — and never where the 25-delta call is bid relative to the 25-delta put.
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Bear call spread golden rules(1) Price the uncovered short call first and then reject it: the wing costs £60.70 and buys back £665.10 of requirement, an unbounded tail and the level at which you are liquidated. If the near wing costs more than half the credit, move it out; do not drop it. (2) Sell only at IV rank 30 or above, and only if the credit clears 20% of the width — never import the put-side 25% rule. (3) Short strike 0.25–0.35 delta and at least +0.5 SD out; both legs the same expiry; one order. (4) Write three numbers before you click: max loss £155.60, breakeven 564.44p, and the 21-DTE date, 25 September 2026. (5) Take 50% of the credit, stop on the first close above the short strike, close at 21 DTE whatever the P&L. (6) Roll out for a credit at the same strikes or not at all — never up, never wider, never for a debit. (7) Close the day the short call's extrinsic value falls under the coming dividend, never let a UK single-stock call spread reach delivery, and log the grant the day you sell it: HMRC's number is £105.10, not £44.40.

What to trade instead

The structure this one replaces: the uncovered short call — the same short 560 call with the wing left unbought. It pays £60.70 more premium and 5.79p more cushion, and gives you in exchange an unlimited loss, £865.10 of requirement rising to £3,304.00 on a bid, a £5,021.70 equity threshold below which one contract liquidates you, and a worse best-case return on capital.

Simpler, from the tier below: if you own the shares, the covered call is this view with collateral behind it instead of a bought option — no margin account, more premium, and a worst case of being made to sell stock you hold. If the view is a genuine fall rather than a ceiling, the long put risks only its premium and pays more the further the share drops.

The same view as a debit: the bear put spread, priced in the table above — it needs BP to fall 4.96% rather than merely not rise 6.50%, is long £1.57 of vega where this is short £1.48, and belongs below IV rank 25. More precise, at this tier: add a bull put spread below the market and you have an iron condor — two credits, one buying-power requirement, two short strikes to watch.

Portfolio fit

One contract contributes −106 share-equivalents of delta, about £560 of short BP exposure, −£1.48 of vega and +£0.29 a day of theta, for £155.60 of buying power — too small to be worth the admin. Three contracts is a position: £466.80 of maximum loss, 1.87% of a £25,000 account, £133.20 of credit. Six such positions on six underlyings is a book — £2,800.80 of maximum loss (11.2% of capital), £3,600 of buying power (14.4%), roughly −£26.66 of net vega and £5.30 a day of theta, inside the 25% buying-power cap this tier works to.

Two caps hold it together, and the second is not the one a put-side book needs. Every position is short vega, so a volatility expansion marks all of it down at once: keep total short vega inside a written number. But the correlation that kills a book of call credit spreads is not a market fall — it is a consolidation wave, where the second bid in a sector follows the first within weeks and two of your six names gap through their short strikes for reasons the index knows nothing about. Six names in three sectors is a book; six names in one sector is a single trade with extra commission. The honest question is whether £2,800.80 leaving in the same month is survivable.

Risk statement

Listed options are complex instruments and a defined-risk spread can still lose its entire defined maximum, quickly and without warning. This is educational material about mechanics, margin and UK tax treatment, not a recommendation to trade BP or anything else, and it takes no account of your circumstances. Every premium and Greek here is modelled rather than quoted, and real fills on thin ICE series are worse. If your trading becomes frequent enough to put the investor-versus-trader boundary in question, that is one for a qualified adviser.

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