QuantConnect/Lean · error · ValueError

Unexpected distribution

Error message

Unexpected distribution: {distribution}

What it means

Per-row sanity check on the AAPL dividend history: every distribution value must be non-zero. A zero distribution indicates malformed dividend data (a dividend row with a 0 amount) or a deserialization bug that zeroed the distribution field.

Solutions

1. Inspect AAPL factor file rows in the window for zero or malformed distribution values.
2. Trace Dividend.Distribution population in the dividend reader/factor provider.
3. Correct or remove the bad data row and re-run.

Example fix

# before: malformed factor row {time; priceFactor; splitFactor; 0 distribution}
# after: corrected distribution value
{20200713;1.0;1.0;0.205}

div = self.history(Dividend, aapl, 360)
bad = [d for d in div.distribution if d == 0]
if bad:
    self.debug(f"zero dividend distributions: {len(bad)}")

def has_nonzero_distributions(div_history) -> bool:
    return all(d != 0 for d in div_history.distribution)

When it happens

Trigger: Iterating dividend.distribution, a value equals 0.0.

Common situations: A factor file row has a zero/blank distribution that was parsed as 0; a dividend refactor changed how Distribution is populated; data corruption.

Related errors

• Unexpected dividend count
• Unexpected multi symbol dividend count
• Unexpected splitfactor
• Unexpected continuous future mapping event count
• Unexpected continuous future mapping event count

AI-assisted analysis of QuantConnect/Lean@d2c3659f87 (2026-08-13). Data as JSON: /api/errors/ae92b06c40988459. Report an issue: GitHub.

Appendix: source

Thrown at Algorithm.Python/HistoryAuxiliaryDataRegressionAlgorithm.py:50

        if len(multi_symbol_request) != 12:
                raise ValueError(f"Unexpected multi symbol dividend count: {len(multi_symbol_request)}")

        # continuous future mapping requests
        sp500 = Symbol.create(Futures.Indices.SP_500_E_MINI, SecurityType.FUTURE, Market.CME)
        continuous_future_open_interest_mapping = self.history(SymbolChangedEvent, sp500, datetime(2007, 1, 1), datetime(2012, 1, 1), data_mapping_mode = DataMappingMode.OPEN_INTEREST)
        if len(continuous_future_open_interest_mapping) != 9:
                raise ValueError(f"Unexpected continuous future mapping event count: {len(continuous_future_open_interest_mapping)}")
        continuous_future_last_trading_day_mapping = self.history(SymbolChangedEvent, sp500, datetime(2007, 1, 1), datetime(2012, 1, 1), data_mapping_mode = DataMappingMode.LAST_TRADING_DAY)
        if len(continuous_future_last_trading_day_mapping) != 9:
                raise ValueError(f"Unexpected continuous future mapping event count: {len(continuous_future_last_trading_day_mapping)}")

        dividend = self.history(Dividend, aapl, 360)
        self.debug(str(dividend))
        if len(dividend) != 6:
            raise ValueError(f"Unexpected dividend count: {len(dividend)}")
        for distribution in dividend.distribution:
            if distribution == 0:
                raise ValueError(f"Unexpected distribution: {distribution}")

        split = self.history(Split, aapl, 360)
        self.debug(str(split))
        if len(split) != 2:
            raise ValueError(f"Unexpected split count: {len(split)}")
        for splitfactor in split.splitfactor:
            if splitfactor == 0:
                raise ValueError(f"Unexpected splitfactor: {splitfactor}")

        symbol = Symbol.create("BTCUSD", SecurityType.CRYPTO_FUTURE, Market.BINANCE)
        margin_interest = self.history(MarginInterestRate, symbol, 24 * 3, Resolution.HOUR)
        self.debug(str(margin_interest))
        if len(margin_interest) != 8:
            raise ValueError(f"Unexpected margin interest count: {len(margin_interest)}")
        for interestrate in margin_interest.interestrate:
            if interestrate == 0:
                raise ValueError(f"Unexpected interestrate: {interestrate}")

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