Option Strategies
Short Straddle
Introduction
A Short Straddle consists of selling a call and a put, where both contracts have the same underlying asset, strike price (normally at-the-money), and expiration date. If you enter a short straddle, you bet that the underlying asset will remain relatively stable and not experience significant price movements before the Option expires.
Implementation
Follow these steps to implement the short straddle strategy:
- In the
initialize
method, set the start date, end date, cash, and Option universe. - In the
on_data
method, select the expiration date and strike price 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, 6, 30) self.set_cash(100000) self.universe_settings.asynchronous = True option = self.add_option("GOOG") self._symbol = option.symbol option.set_filter(lambda universe: universe.include_weeklys().straddle(30))
The straddle
filter narrows the universe down to just the two contracts you need to form a short straddle.
def on_data(self, slice: Slice) -> None: if self.portfolio.invested: return chain = slice.option_chains.get(self._symbol, None) if not chain: return # Find ATM options with the nearest expiry expiry = min([x.expiry for x in chain]) strike = sorted(chain, key=lambda x: abs(x.strike - chain.underlying.price))[0].strike
Approach A: Call the OptionStrategies.short_straddle
method with the details of each leg and then pass the result to the buy
method.
short_straddle = OptionStrategies.short_straddle(self._symbol, contracts[0].strike, expiry) self.buy(short_straddle, 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.
contracts = [x for x in chain if x.expiry == expiry and x.strike == strike] if len(contracts) < 2: return atm_call = [x for x in contracts if x.right == OptionRight.CALL][0] atm_put = [x for x in contracts if x.right == OptionRight.PUT][0] legs = [ Leg.create(atm_call.symbol, -1), Leg.create(atm_put.symbol, -1) ] self.combo_market_order(legs, 1)
Strategy Payoff
The payoff of the strategy is
CATMT=(ST−KC)+PATMT=(KP−ST)+PT=(−CATMT−PATMT+CATM0+PATM0)×m−feeThe following chart shows the payoff at expiration:

The maximum profit is CATM0+PATM0. It occurs when the price of the underlying asset remains exactly at the strike price upon expiration.
The maximum loss is unlimited if the underlying price rises to infinity or drops to zero at expiration.
If the Option is American Option, there is a risk of early assignment on the contracts you sell.
Example
The following table shows the price details of the assets in the algorithm at Option expiration (2017-05-20):
Asset | Price ($) | Strike ($) |
---|---|---|
Call | 19.6 | 835.00 |
Put | 21.4 | 835.00 |
Underlying Equity at early (2017-05-15) call assignment | 932.22 | - |
Underlying Equity at expiration | 934.01 | - |
Therefore, the payoff is
CATMT=(ST−KC)+=(934.01−835.00)+=99.01PATMT=(KP−ST)+=(835.00−934.01)+=0PT=(−CATMT−PATMT+CATM0+PATM0)×m−fee=(−99.01−0+19.6+21.4)×100−2.00=−5803So, the strategy loses $5,277. The early assigment doesn't influence the payoff.
The following algorithm implements a short straddle Option strategy:
class LongStraddleAlgorithm(QCAlgorithm): def initialize(self) -> None: self.set_start_date(2017, 4, 1) self.set_end_date(2017, 6, 30) self.set_cash(100000) option = self.add_option("GOOG") self.symbol = option.symbol option.set_filter(lambda universe: universe.include_weeklys().straddle(30)) def on_data(self, slice: Slice) -> None: if self.portfolio.invested: return chain = slice.option_chains.get(self.symbol, None) if not chain: return # Find ATM options with the nearest expiry expiry = min([x.expiry for x in chain]) contracts = sorted([x for x in chain if x.expiry == expiry], key=lambda x: abs(chain.underlying.price - x.strike)) if len(contracts) < 2: return # The first two contracts are the ATM Call and the ATM Put contracts = contracts[0:2] short_straddle = OptionStrategies.short_straddle(self.symbol, contracts[0].strike, expiry) self.buy(short_straddle, 1)