Hi friends,

I'm having troubles when making backtest. I find quite error messages related to data for some symbols, so I would like you to help me.

I have the following strategy:

import numpy as np

class BetaAlgorithm(QCAlgorithm):

def Initialize(self):
self.SetStartDate(2020, 8, 20) # Set Start Date
self.SetEndDate(2020, 10, 26) # Set End Date
self.SetCash(10000) # Set Strategy Cash

self.ReductionCoeff = 0.98 # Coefficient to avoid leverage
self.PositionsNumber = 5 # Max. number of active positions for this strategy

self.spy = self.AddEquity("QQQ", Resolution.Daily) # Add equity to use for trends

# Dow 30 companies.
self.symbols = [self.AddEquity(ticker).Symbol

for ticker in [
'GH', # Guardant Health
'GWRE', # Guidewire Software
'HUBS', # HubSpot
'IBKR', # Interactive Brokers Group
'INCY', # Incyte Corporation
'IONS', # Ionis Pharmaceuticals
'IOVA', # Iovance Biotherapeutics
'IRDM', # Iridium Communications
'KTOS', # Kratos Defense & Security Solutions
'LMND', # Lemonade
'LSPD', # Lightspeed POS
'MCRB', # Seres Therapeutics
'MKL', # Markel Corporation
] ]

# Benchmark - Security used as reference to beat. In this case QQQ (NASDAQ index)
self.benchmark = Symbol.Create('QQQ', SecurityType.Equity, Market.USA)

# Set number days to trace back
self.lookback = 1

# Schedule Event: trigger the event at the begining of each month.

#QQQ trend filter: only trades if benchmark trends
# Very fast moving average of benchmark
self.spy_ma_vfast = self.EMA("QQQ", 5)
# Fast moving average of benchmark
self.spy_ma_fast = self.EMA("QQQ", 13)
# Slow moving average of benchmark
self.spy_ma_slow = self.EMA("QQQ", 21)

def Rebalance(self):

# Defines benchmark in a trend (fast ma over slow ma)
self.trend_up = self.spy_ma_vfast > self.spy_ma_fast and self.spy_ma_fast > self.spy_ma_slow

# Fetch the historical data to perform the linear regression

history = self.History(

self.symbols + [self.benchmark],

symbols = self.SelectSymbols(history)

# Liquidate positions that are not held by selected symbols and liquidates if benchmark is not in a trend
for holdings in self.Portfolio.Values:
symbol = holdings.Symbol
if symbol not in symbols and holdings.Invested:

# Invest in the selected symbols is benchmark/reference is in a trend
for symbol in symbols:

if self.trend_up:
# Position size is calculated based on active strategies, max positions number and some coeffs to avoid leverage
self.SetHoldings(symbol, (1*self.ReductionCoeff)/self.PositionsNumber)

if not self.trend_up:

def SelectSymbols(self, history):
'''Select symbols with the highest intercept/alpha to the benchmark'''

alphas = dict()

# Get the benchmark returns
benchmark = history[self.benchmark].pct_change().dropna()

# Conducts linear regression for each symbol and save the intercept/alpha
for symbol in self.symbols:

# Get the security returns
returns = history[symbol].pct_change().dropna()
returns = np.vstack([returns, np.ones(len(returns))]).T

# Simple linear regression function in Numpy
result = np.linalg.lstsq(returns, benchmark)
alphas[symbol] = result[0][1]

# Select symbols and number of them with the highest intercept/alpha to the benchmark
selected = sorted(alphas.items(), key=lambda x: x[1], reverse=True)[:self.PositionsNumber]
return [x[0] for x in selected]


But I'm getting the following error:

BacktestingRealTimeHandler.Run(): There was an error in a scheduled event EveryDay: FVRR: 0 min after MarketOpen. The error was KeyError : 'LSPD XHRUTPA72AG5'

If I try an older Start Date, it shows more error in different tickers.

Is there any way to fix this or pass the error? It happens even in other strategies using coarse and fine selection but at this moment this is the one I would like to fix.

Thanks in advance and kind regards.