HKUDS/Vibe-Trading · error · ValueError

preferred rate must be non-negative, got {rate!r}

Error message

preferred rate must be non-negative, got {rate!r}

What it means

preferred_return_amount validates its hurdle rate and rejects negative values because the compounding convention for a negative preferred rate is undefined. Only rate >= 0 is accepted.

Source

Thrown at agent/src/quantlib/fundmath.py:961

        compounding: One of :data:`PREFERRED_COMPOUNDING`. ``"compound"``
            accrues ``(1 + rate) ** years - 1``; ``"simple"`` accrues
            ``rate * years``.
        days_per_year: Day basis for the year fraction.
        contribution_kinds: Kind labels counted as capital in.

    Returns:
        The preferred return owed, as a positive magnitude excluding the return
        of capital itself. ``0.0`` when nothing has been drawn.

    Raises:
        TypeError: If ``series`` is not a ``CashFlowSeries``.
        ValueError: If the rate is negative, the compounding convention is
            unknown, ``as_of`` precedes a contribution, or ``as_of`` is omitted
            for an empty series.
    """
    _require_series(series)
    if rate < 0.0:
        raise ValueError(f"preferred rate must be non-negative, got {rate!r}")
    if compounding not in PREFERRED_COMPOUNDING:
        raise ValueError(
            f"compounding={compounding!r} is not one of {PREFERRED_COMPOUNDING}"
        )
    if days_per_year <= 0:
        raise ValueError(f"days_per_year must be positive, got {days_per_year!r}")

    contributions = tuple(series.filter(kind=contribution_kinds))
    if not contributions:
        return 0.0

    if as_of is None:
        if series.is_empty:
            raise ValueError("as_of is required for an empty series")
        measurement = max(series.dates())
    else:
        measurement = normalize_date(as_of, field_name="as_of")

View on GitHub (pinned to 80ffdda44c)

Solutions

1. Pass the rate as a non-negative decimal (0.08 for 8%)
2. Check the config/parse step that produced the negative value
3. Use 0.0 explicitly for a no-hurdle fund

Example fix

# before
preferred_return_amount(series, rate=-0.08)

# after
preferred_return_amount(series, rate=0.08)

if rate < 0:
    raise ConfigError(f"hurdle rate must be >= 0, got {rate}")

When it happens

Trigger: Calling preferred_return_amount(series, rate=-0.08) (or european_waterfall/_pooled_entitlement with a negative hurdle rate parameter).

Common situations: Parsing a hurdle like '-8' from config when it was meant as 8%; sign errors when converting an annual rate; unit tests passing negative fixtures.

Related errors

• compounding={compounding!r} is not one of {PREFERRED_COMPOUN
• as_of is required for an empty series
• contribution on {flow.date} is after as_of={measurement}; a
• {label} must be non-negative, got {value!r}
• invalid alpha_id

AI-assisted analysis of HKUDS/Vibe-Trading@80ffdda44c (2026-08-28). Data as JSON: /api/errors/3bea6e4969fbe80b. Report an issue: GitHub.