OpenBB-finance/OpenBB · error · ValueError

Invalid region, '{region}', for factor '{factor}'. Only 'ame

Error message

Invalid region, '{region}', for factor '{factor}'. Only 'america' is supported.

What it means

Fama-French factors query-model validator: the short-term and long-term reversal factors ('st_reversal', 'lt_reversal') exist only in the North American dataset, so requesting them with region != 'america' raises this ValueError during parameter validation, before any network call.

Source

Thrown at openbb_platform/providers/famafrench/openbb_famafrench/models/factors.py:122

        description="End date of the data. Defaults to the complete data range.",
        json_schema_extra={
            "x-widget_config": {
                "value": "$currentDate",
                "description": "End date of the factor data.",
            }
        },
    )

    @model_validator(mode="before")
    @classmethod
    def validate_region_and_factor(cls, values):
        """Validate region and factor combination."""
        region = values.get("region", "america")
        factor = factors_dict.get(values.get("factor", "3_factors"), "")
        frequency = values.get("frequency", "")

        if factor and factor in ["st_reversal", "lt_reversal"] and region != "america":
            raise ValueError(
                f"Invalid region, '{region}', for factor '{factor}'. Only 'america' is supported."
            )

        if region and region not in list(FACTOR_REGION_MAP):
            raise ValueError(
                f"Invalid region: '{region}'. "
                + "Valid regions are: "
                + ", ".join(FACTOR_REGION_MAP.keys())
            )

        regional_factors = FACTOR_REGION_MAP[region]

        if factor not in regional_factors.get("factors", {}):
            raise ValueError(
                f"Invalid factor: '{factor}' for region: '{region}'. "
                + "Valid factors are: "
                + ", ".join(regional_factors.get("factors", {}).keys())
            )

View on GitHub (pinned to 3e071fcc2c)

Solutions

Set region='america' when requesting st_reversal or lt_reversal.
Or choose a factor that exists in your target region (see FACTOR_REGION_MAP[region]['factors']).
Build region-aware factor lists in your UI from FACTOR_REGION_MAP instead of a flat list.

Example fix

# before
Fetcher(query={'factor': 'st_reversal', 'region': 'europe'})

# after
Fetcher(query={'factor': 'st_reversal', 'region': 'america'})

Defensive patterns

Strategy: validation

Validate before calling

AMERICA_ONLY = {'st_reversal', 'lt_reversal'}

def combo_ok(region: str, factor: str) -> bool:
    return factor not in AMERICA_ONLY or region == 'america'

Try / catch

try:
    res = await obb.economy.famafrench.factors(factor=f, region=r, provider='famafrench')
except ValueError as e:
    if 'Only \'america\' is supported' in str(e):
        r = 'america'
        res = await obb.economy.famafrench.factors(factor=f, region=r, provider='famafrench')
    else:
        raise

Prevention

Special-case reversal factors in region-aware UIs
Validate (region, factor) pairs before batch submission

When it happens

Trigger: Calling the Fama-French factors endpoint with factor='st_reversal' (or 'lt_reversal') and region='europe'/'japan'/'asia_pacific_ex_japan'/'north_america'/etc.

Common situations: Reusing a parameter set across regions in batch jobs; UIs that list all factors regardless of selected region; users assuming reversal factors are global like the 3/5-factor models.

Related errors

AI-assisted analysis of OpenBB-finance/OpenBB@3e071fcc2c (2026-08-14). Data as JSON: /api/errors/c02ec01f1fec5b3d. Report an issue: GitHub.