nautechsystems/nautilus_trader · error

Invalid multiplier {}: {e}

Error message

Invalid multiplier {}: {e}

What it means

parse_instrument_multiplier converts a BitMEX quanto instrument's multiplier into a Nautilus Quantity. For quanto contracts it converts the f64 multiplier to Decimal; if Decimal::try_from fails (NaN, infinite, or otherwise unrepresentable), the f64 value and the conversion error are wrapped in this message.

Source

Thrown at crates/adapters/bitmex/src/http/parse.rs:563

        .taker_fee(taker_fee)
        .ts_event(ts_event)
        .ts_init(ts_init)
        .build()
        .unwrap();

    Ok(InstrumentAny::CryptoFuture(instrument))
}

fn parse_instrument_multiplier(
    definition: &BitmexInstrument,
    settlement_currency: Currency,
) -> anyhow::Result<Quantity> {
    if !definition.is_quanto {
        return Quantity::new_checked(definition.multiplier.abs(), 0).map_err(Into::into);
    }

    let raw = Decimal::try_from(definition.multiplier.abs())
        .map_err(|e| anyhow::anyhow!("Invalid multiplier {}: {e}", definition.multiplier))?;
    let bitmex_currency = definition
        .settl_currency
        .as_ref()
        .unwrap_or(&definition.quote_currency);
    let divisor = bitmex_currency_divisor(bitmex_currency.as_str());
    let value = raw.checked_div(divisor).ok_or_else(|| {
        anyhow::anyhow!("Invalid multiplier divisor {divisor} for {bitmex_currency}")
    })?;

    Quantity::from_decimal_dp(value, settlement_currency.precision).map_err(Into::into)
}

/// Parse a BitMEX futures spread instrument into a Nautilus `InstrumentAny`.
///
/// # Errors
///
/// Returns an error if values are out of valid range or cannot be parsed.
///

View on GitHub (pinned to 18893faf8b)

Solutions

1. Log the full instrument definition (symbol, multiplier, settl_currency) to identify the offending contract.
2. Skip or exclude the affected symbol from the instrument load list if it is not needed.
3. Check for a newer nautilus_bitmex adapter version that handles the multiplier representation.
4. Report/verify against the BitMEX /instrument endpoint whether the multiplier is genuinely non-finite.

if definition.is_quanto && !definition.multiplier.is_finite() {
    log::warn!("skipping {} : non-finite multiplier", definition.symbol);
    return Ok(None);
}

match parse_perpetual_instrument(&definition, ...) {
    Ok(inst) => Some(inst),
    Err(e) if e.to_string().contains("Invalid multiplier") => {
        log::warn!("skipping instrument: {e}"); None
    }
    Err(e) => return Err(e),
}

When it happens

Trigger: Parsing a perpetual or futures instrument definition whose is_quanto is true and whose multiplier is NaN, infinite, or cannot be represented as a fixed-point Decimal.

Common situations: BitMEX listing a new/odd contract with an anomalous multiplier field; corrupted or partially-updated instrument definition responses; float serialization changes from the venue API.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• Invalid multiplier divisor {divisor} for {bitmex_currency}
• invalid {field} `{raw}`
• Order missing order_qty and cannot reconstruct (order_id={},
• Skipping non-trade execution: {:?}
• Skipping execution without side: {:?}

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/4ee865a7d7f33139. Report an issue: GitHub.