Quant Buffet放轻松,别过度思虑

横截面六个月股票平值(Straddle) 交易策略

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学术论文

Understanding and Trading the Term Structure of Volatility

作者Jump Risk and Option Returns [点击查看论文]

机构
  • Kansas State University
  • University of Massachusetts Amherst
  • ?Kansas State University - Department of Finance
  • ?University of Massachusetts Amherst - Isenberg School of Management
  • ?Isenberg School of Management, University of Massachusetts

策略概要

投资范围包括所有美国股票期权,重点是每月期权到期后形成的平值跨式期权。排除违反套利条件或标的股票价格低于10美元的期权。仅包括delta在±0.35至±0.65之间的平值期权。投资组合基于隐含波动率期限结构的斜率。跨式期权根据其斜率分为十分位数,第一十分位数包含波动率斜率最大的期权。该策略从第一十分位数买入,从第十分位数卖出,持有至到期。投资组合等权重,并由于策略的偏度风险,将投资限制在20%。

II. 策略合理性

该策略的功能基于一个原则,即风险的价格在较长的时间范围内会降低。这种关系适用于各种资产类别,表明了投资者风险偏好的一个基本方面。隐含波动率期限结构与短期到期期权价格的过度反应相关,不同时间范围内的已实现波动率有助于解释短期和长期到期隐含波动率。波动率期限结构的斜率与短期到期期权的波动率风险溢价之间存在很强的联系。随着期限结构反转,短期风险溢价增加,而长期风险溢价减少,显示出与回报的负相关。

回测表现

波动率18.46%
夏普比率1.7
索提诺比率-0.96
胜率24%

完整 Python 代码

from AlgorithmImports import *
from typing import List, Dict
from pandas.core.frame import DataFrame
from pandas.core.series import Series
#endregion
class CrossSectionalSixMonthEquityATMStraddleTradingStrategy(QCAlgorithm):
def Initialize(self) -> None:
self.SetStartDate(2015, 1, 1)
self.SetCash(1000000)

self.min_expiry: int = 180
self.max_expiry: int = 240

self.period: int = 6 * 21 # need n of stock daily prices
self.percentage_traded: float = 0.1
self.selection_threshold: int = 10
self.min_share_price: int = 10
self.quantile: int = 10
self.leverage: int = 10

self.data: Dict[Symbol, RollingWindow[float]] = {}
self.symbols_by_ticker: Dict[str, Symbol] = {}
self.subscribed_contracts: Dict[Symbol, Contracts] = {}

symbol: Symbol = self.AddEquity('SPY', Resolution.Daily).Symbol

self.day: int = -1
self.fundamental_count: int = 100
self.fundamental_sorting_key = lambda x: x.DollarVolume
self.selection_flag: bool = False
self.settings.daily_precise_end_time = False
self.Settings.MinimumOrderMarginPortfolioPercentage = 0.
self.UniverseSettings.Resolution = Resolution.Daily
self.AddUniverse(self.FundamentalSelectionFunction)
self.UniverseSettings.DataNormalizationMode = DataNormalizationMode.Raw
self.Schedule.On(self.DateRules.MonthStart(symbol), self.TimeRules.BeforeMarketClose(symbol), self.Selection)
def OnSecuritiesChanged(self, changes: SecurityChanges) -> None:
for security in changes.AddedSecurities:
    security.SetFeeModel(CustomFeeModel())
    security.SetLeverage(self.leverage)
def FundamentalSelectionFunction(self, fundamental: List[Fundamental]) -> List[Symbol]:
# update daily prices of stocks in self.data dictionary
for stock in fundamental:
    symbol:Symbol = stock.Symbol
    
    if symbol in self.data:
        self.data[symbol].Add(stock.AdjustedPrice)

# rebalance monthly
if not self.selection_flag:
    return Universe.Unchanged

# select top n stocks by dollar volume
selected: List[Fundamental] = [
    x for x in fundamental if x.HasFundamentalData and x.Market == 'usa' and x.Price > self.min_share_price
]

if len(selected) > self.fundamental_count:
    selected = [x for x in sorted(selected, key=self.fundamental_sorting_key, reverse=True)[:self.fundamental_count]]
        
for stock in selected:
    symbol: Symbol = stock.Symbol
    ticker: str = symbol.Value 
    self.symbols_by_ticker[ticker] = symbol
    
    if symbol in self.data:
        continue
    
    self.data[symbol] = RollingWindow[float](self.period)
    history: DataFrame = self.History(symbol, self.period, Resolution.Daily)
    if history.empty:
        continue
    closes: Series = history.loc[symbol].close
    for time, close in closes.items():
        self.data[symbol].Add(close)
# return newly selected symbols
return list(map(lambda x: x.Symbol, selected))
def OnData(self, data: Slice) -> None:
# execute once a day
if self.day == self.Time.day:
    return
self.day = self.Time.day

# subscribe to new contracts after selection
if len(self.subscribed_contracts) == 0 and self.selection_flag:
    for _, symbol in self.symbols_by_ticker.items():
        if self.Securities[symbol].IsDelisted:
            continue
        if symbol in data and data[symbol]:
            if symbol in self.data and self.data[symbol].IsReady:
                # get all contracts for current stock symbol
                contracts: List[Symbol] = self.OptionChainProvider.GetOptionContractList(symbol, self.Time)
                # get current price for etf
                underlying_price: float = self.data[symbol][0]
                
                # get strikes from commodity future contracts
                strikes: List[float] = [i.ID.StrikePrice for i in contracts]
                
                # can't filter contracts, if there isn't any strike price
                if len(strikes) <= 0 or underlying_price == 0:
                    continue
                
                # filter calls and puts contracts with one month expiry
                calls, puts = self.FilterContracts(strikes, contracts, underlying_price)
                
                # make sure, there is at least one call and put contract
                if len(calls) > 0 and len(puts) > 0:
                    # sort by expiry
                    call: Symbol = sorted(calls, key = lambda x: x.ID.Date, reverse=True)[0]
                    put: Symbol = sorted(puts, key = lambda x: x.ID.Date, reverse=True)[0]
                    
                    subscriptions = self.SubscriptionManager.SubscriptionDataConfigService.GetSubscriptionDataConfigs(call.Underlying)
                    if subscriptions:
                        # add call contract
                        self.AddContract(call)
                        # add put contract
                        self.AddContract(put)
                        
                        # retrieve expiry date for contracts
                        expiry_date: dateTime.date = call.ID.Date.date()
                        # store contracts with expiry date under stock's symbol
                        self.subscribed_contracts[symbol] = Contracts(expiry_date, underlying_price, [call, put])
        
# calculate term structure and trade options
elif len(self.subscribed_contracts) != 0 and data.OptionChains.Count != 0 and self.selection_flag:
    self.selection_flag = False # this makes sure, there will be no other trades until next selection
    
    term_structure: Dict[Symbol, float] = {} # storing term structures keyed by stock's symbol
    
    for kvp in data.OptionChains:
        chain: OptionChain = kvp.Value
        
        ticker: str = chain.Underlying.Symbol.Value
        if ticker in self.symbols_by_ticker:
            # get stock's symbol
            symbol: Symbol = self.symbols_by_ticker[ticker]
            if symbol in data and data[symbol]:
                # get contracts
                contracts: List[Symbol] = [x for x in chain]
                
                # check if there are enough contracts for option and daily prices are ready
                if len(contracts) < 2 or not self.data[symbol].IsReady:
                    continue
                
                # get call and put implied volatility
                call_iv, put_iv = self.GetImpliedVolatilities(contracts)
                
                if call_iv and put_iv:
                    # make mean from call implied volatility and put implied volatility
                    iv: float = (call_iv + put_iv) / 2 
                    # get historical volatility
                    hv: float = self.GetHistoricalVolatility(self.data[symbol])
                    
                    # store stock's term structure
                    term_structure[symbol] = (iv - hv) / hv
        
    # can't perform selection
    if len(term_structure) < self.selection_threshold:
        return
    
    # perform quantile selection
    quantile: int = int(len(term_structure) / self.quantile)
    sorted_by_term_structure: List[Symbol] = [x[0] for x in sorted(term_structure.items(), key=lambda item: item[1])]
    
    # long bottom
    long: List[Symbol] = sorted_by_term_structure[:quantile]
    # short top
    short: List[Symbol] = sorted_by_term_structure[-quantile:]
    
    # trade long
    self.TradeOptions(data, long, True)
    # trade short
    self.TradeOptions(data, short, False)
    
def Selection(self) -> None:
self.selection_flag = True  # perform new selection
self.Liquidate()            # rebalance monthly, so liquidate all holdings

# clear dictionary for subscribed contracts, because there will be new selection
self.subscribed_contracts.clear()
# clear dictionary of tickers and their symbols, because new stocks will be selected
self.symbols_by_ticker.clear()

def FilterContracts(self, strikes: List[float], contracts: List[Symbol], underlying_price: float) -> List[Symbol]:
''' filter call and put contracts from contracts parameter '''
''' return call and put contracts '''

# straddle
call_strike: float = min(strikes, key=lambda x: abs(x-underlying_price))
put_strike: float = call_strike

calls: List[Symbol] = []  # storing call contracts
puts: List[Symbol] = []   # storing put contracts

for contract in contracts:
    # check if contract has six months expiry
    if self.min_expiry < (contract.ID.Date - self.Time).days < self.max_expiry:
        # check if contract is call
        if contract.ID.OptionRight == OptionRight.Call and contract.ID.StrikePrice == call_strike:
            calls.append(contract)
        # check if contract is put
        elif contract.ID.OptionRight == OptionRight.Put and contract.ID.StrikePrice == put_strike:
            puts.append(contract)

# return filtered calls and puts with one month expiry
return calls, puts

def AddContract(self, contract: Symbol) -> None:
''' subscribe option contract, set price mondel and normalization mode '''
option: Option = self.AddOptionContract(contract, Resolution.Daily)
option.PriceModel = OptionPriceModels.CrankNicolsonFD()

def GetImpliedVolatilities(self, contracts: List[Symbol]) -> List[float]:
''' retrieve implied volatility of contracts from contracts parameteres '''
''' returns call and put implied volatility '''
call_iv: Union[None, float] = None
put_iv: Union[None, float] = None
        
# go through option contracts
for c in contracts:
    if c.Right == OptionRight.Call:
        # found call option
        call_iv = c.ImpliedVolatility
    else:
        # found put option
        put_iv = c.ImpliedVolatility
    
return call_iv, put_iv

def GetHistoricalVolatility(self, rolling_window_prices: RollingWindow) -> float:
''' calculate historical volatility based on daily prices in rolling_window_prices parameter '''
prices: np.ndarray = np.array([x for x in rolling_window_prices])
returns: np.ndarray = (prices[:-1] - prices[1:]) / prices[1:]
return np.std(returns)

def TradeOptions(self, data: Slice, symbols: List[Symbol], long_flag: bool):
''' on long signal buy call and put option contract '''
''' on short signal sell call and put option contract '''
count: int = len(symbols)

# trade etf's call and put contracts
for symbol in symbols:
    if symbol in self.subscribed_contracts:
        # check if contracts are tradebale and don't have 0 price
        # for contract in self.subscribed_contracts[symbol].contracts:
        #     if not self.Securities[contract].IsTradable or self.Securities[contract].Price == 0:
        #         return

        # get call and put contract
        call, put = self.subscribed_contracts[symbol].contracts
        # get underlying price
        underlying_price: float = self.subscribed_contracts[symbol].underlying_price
        
        options_q: int = int(((self.Portfolio.MarginRemaining * self.percentage_traded) / count) / (underlying_price * 100))
        
        if call in data and data[call] and put in data and data[put]:
            if long_flag:
                self.Buy(call, options_q)
                self.Buy(put, options_q)
            else:
                self.Sell(call, options_q)
                self.Sell(put, options_q)

class Contracts():
def __init__(self, expiry_date: datetime.date, underlying_price: float, contracts: List[Symbol]):
self.expiry_date: datetime.date = expiry_date
self.underlying_price: float = underlying_price
self.contracts: List[Symbol] = contracts
# Custom fee model
class CustomFeeModel(FeeModel):
def GetOrderFee(self, parameters: OrderFeeParameters) -> OrderFee:
fee: float = parameters.Security.Price * parameters.Order.AbsoluteQuantity * 0.00005
return OrderFee(CashAmount(fee, "USD"))