HKUDS/Vibe-Trading · error · ValueError

contribution on {flow.date} is after as_of={measurement}; a

Error message

contribution on {flow.date} is after as_of={measurement}; a preferred return cannot accrue backwards

What it means

Preferred return accrues forward from each contribution date to the measurement date; a contribution dated after as_of would imply negative accrual time, which the function refuses rather than returning a negative hurdle.

Source

Thrown at agent/src/quantlib/fundmath.py:984

    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")

    total = 0.0
    for flow in contributions:
        years = (measurement - flow.date).days / days_per_year
        if years < 0.0:
            raise ValueError(
                f"contribution on {flow.date} is after as_of={measurement}; a "
                "preferred return cannot accrue backwards"
            )
        principal = -flow.amount
        if compounding == "compound":
            total += principal * ((1.0 + rate) ** years - 1.0)
        else:
            total += principal * rate * years
    return total


@dataclass(frozen=True)
class WaterfallTier:
    """One tier of a distribution waterfall and how it split.

    Attributes:
        name: Tier label, one of the ``TIER_*`` constants.
        amount: Dollars that flowed through this tier.

View on GitHub (pinned to 80ffdda44c)

Solutions

1. Move as_of to on or after the latest contribution date (e.g. the latest mark date via _default_as_of semantics)
2. Fix misparsed dates (day/month swap) in the contribution records

Example fix

# before
preferred_return_amount(series, rate=0.08, as_of="2024-01-01")  # draw on 2024-06-30

# after
preferred_return_amount(series, rate=0.08, as_of="2024-12-31")

last_contrib = max(f.date for f in series.filter(kind=CONTRIB_KINDS))
if as_of is None:
    as_of = max(last_contrib, *series.dates())
else:
    assert as_of >= last_contrib, f"as_of {as_of} predates draw {last_contrib}"

When it happens

Trigger: Calling preferred_return_amount(series, rate=0.08, as_of=date(2024,1,1)) when the series contains a contribution dated 2024-06-30 — i.e. as_of predates a draw.

Common situations: Measuring 'as of' a quarter-end that precedes a later capital call; date parsing that swaps day/month producing future dates; stale as_of defaults.

Related errors

• preferred rate must be non-negative, got {rate!r}
• compounding={compounding!r} is not one of {PREFERRED_COMPOUN
• as_of is required for an empty series
• latest valuation on {marks[-1].date} is {value!r}; a residua
• paid-in capital is {paid_in!r}; a capital multiple is undefi

AI-assisted analysis of HKUDS/Vibe-Trading@80ffdda44c (2026-08-28). Data as JSON: /api/errors/12b1061c73d61edd. Report an issue: GitHub.