Option Strategies
Short Call Backspread
Introduction
Short Call Backspread, consists of long 1 lower-strike call and short 2 higher strike calls. It is a combination of a bull call spread and a short call with the same strike price as the higher-strike leg the call spread. All calls have the same underlying Equity and expiration date. This strategy profits from stable, consistent price of the underlying asset. For instance, the underlying price stays at its current price.
Implementation
Follow these steps to implement the short call backspread strategy:
- In the
initialize
method, set the start date, end date, cash, and Option universe. You can use thecall_spread
helper method in option universe filtering, since a call backspread consists of the same contracts as a call spread. - In the
on_data
method, select the expiration and strikes of the contracts in the strategy legs. - In the
on_data
method, select the contracts and place the orders.
def initialize(self) -> None: self.set_start_date(2017, 4, 1) self.set_end_date(2017, 4, 22) self.set_cash(1000000) self.universe_settings.asynchronous = True option = self.add_option("GOOG", Resolution.MINUTE) self._symbol = option.symbol option.set_filter(lambda universe: universe.include_weeklys().call_spread(20, 5))
def on_data(self, slice: Slice) -> None: if self.portfolio.invested: return # Get the OptionChain chain = slice.option_chains.get(self._symbol, None) if not chain: return # Select the call Option contracts with the furthest expiry expiry = max([x.expiry for x in chain]) calls = [i for i in chain if i.expiry == expiry and i.right == OptionRight.CALL] if not calls: return # Select the strike prices from the remaining contracts strikes = sorted(set(x.strike for x in calls)) if len(strikes) < 2: return low_strike = strikes[0] high_strike = strikes[1]
Approach A: Call the OptionStrategies.short_call_backspread
method with the details of each leg and then pass the result to the buy
method.
option_strategy = OptionStrategies.short_call_backspread(self._symbol, low_strike, high_strike, expiry) self.buy(option_strategy, 1)
Approach B: Create a list of Leg
objects and then call the combo_market_order, combo_limit_order, or combo_leg_limit_order method.
low_strike_call = next(filter(lambda x: x.strike == low_strike, calls)) high_strike_call = next(filter(lambda x: x.strike == high_strike, calls)) legs = [ Leg.create(low_strike_call.symbol, 1), Leg.create(high_strike_call.symbol, -2) ] self.combo_market_order(legs, 1)
Strategy Payoff
The short call backspread is an limited-profit-unlimited-risk strategy. The payoff is
ClowT=(ST−Klow)+ChighT=(ST−Khigh)+PayoffT=(ClowT−Clow0+Chigh0×2−ChighT×2)×m−fee whereClowT=Lower-strike call value at time TChighT=Higher-strike call value at time TST=Underlying asset price at time TKlow=Lower-strike call strike priceKhigh=Higher-strike call strike priceClow0=Lower-strike call value at position opening (credit received)Chigh0=Higher-strike call value at position opening (debit paid)m=Contract multiplierT=Time of expirationThe following chart shows the payoff at expiration:

The maximum profit is Khigh−Klow−Clow0+Chigh0×2, which occurs when the underlying price is exactly at the higher strike at expiry.
The maximum loss is unlimited, which occurs when the underlying price increases indefinitely.
If the Option is American Option, there is a risk of early assignment on the contract you sell.
Example
The following table shows the price details of the assets in the algorithm:
Asset | Price ($) | Strike ($) |
---|---|---|
Lower-Strike call | 15.10 | 825.00 |
Higher-strike call | 8.00 | 835.00 |
Underlying Equity at expiration | 843.19 | - |
Therefore, the payoff is
ClowT=(ST−Klow)+=(843.19−825.00)+=18.19ChighT=(ST−Khigh)+=(843.19−835.00)+=8.19PayoffT=(ClowT−Clow0−ChighT×2+Chigh0×2)×m−fee=(18.19−15.10−8.19×2+8.00×2)×100−2.30=268.70So, the strategy gains $268.70.
The following algorithm implements a short call backspread Option strategy:
class BackspreadOptionStrategyAlgorithm(QCAlgorithm): def initialize(self) -> None: self.set_start_date(2017, 4, 1) self.set_end_date(2017, 4, 22) self.set_cash(1000000) self.universe_settings.asynchronous = True option = self.add_option("GOOG", Resolution.MINUTE) self._symbol = option.symbol option.set_filter(lambda universe: universe.include_weeklys().call_spread(20, 5)) def on_data(self, slice: Slice) -> None: if self.portfolio.invested: return # Get the OptionChain chain = slice.option_chains.get(self._symbol, None) if not chain: return # Select the call Option contracts with the furthest expiry expiry = max([x.expiry for x in chain]) calls = [i for i in chain if i.expiry == expiry and i.right == OptionRight.CALL] if not calls: return # Select the strike prices from the remaining contracts strikes = sorted(set(x.strike for x in calls)) if len(strikes) < 2: return low_strike = strikes[0] high_strike = strikes[1] option_strategy = OptionStrategies.short_call_backspread(self._symbol, low_strike, high_strike, expiry) self.buy(option_strategy, 1)