A marketplace sale

Two parties know different halves of this. You know a platform facilitated the sale and took on collection — nothing in a rate table can know that. The register knows whether the law of the place of supply moves the liability because of it.

$assessment = app(TaxCalculator::class)->assess(new TaxQuery(
    amount: Money::of('100.00', 'GBP'),
    pricing: Pricing::Exclusive,
    place: $geo->find(new CountryCode('GB')),
    customer: CustomerType::Consumer,
    seller: $seller->taxRegistrations(),
    suppliedAt: $sale->completedAt,
    marketplaceFacilitated: true,          // your assertion about the arrangement
));

Three things can come back, and they are not variations of "zero":

Treatment	What happened
`MarketplaceFacilitated`	The law makes the platform liable. The seller charges nothing, and most places still expect the sale reported and then deducted.
`Standard`	No deeming rule reaches this place, so the assertion changed nothing and the seller's own obligation stands.
`Standard`, with `RateLimit::MarketplaceLiabilityUnread` on the rate	A rule exists and reaches only some facilitated sales. The seller keeps charging, and the flag says the question is open.

The third is the EU today. Article 14a deems an electronic interface the supplier for two specific limbs — a distance sale of imported goods in a consignment worth at most EUR 150, or goods already in the Community sold by a seller established outside it to a customer who is not a taxable person — and the register publishes those conditions typed. This engine does not evaluate them yet, so it does the recoverable thing: the seller charges, and the assessment says the liability was not settled. Reading the rule as a blanket mandate would hand the tax to a platform the Directive does not reach, and then nobody collects it.

$assessment->rate?->limitedBy === RateLimit::MarketplaceLiabilityUnread;

Deciding it yourself

If you know your own platform's position — you are the interface, and you have taken legal advice on which of your sales Article 14a reaches — bind MarketplaceRules and answer directly:

use Cbox\Tax\Contracts\MarketplaceRules;
use Cbox\Tax\Enums\MarketplaceLiability;

$this->app->bind(MarketplaceRules::class, fn () => new class implements MarketplaceRules
{
    public function liability(CountryCode $country, DateTimeImmutable $on): MarketplaceLiability
    {
        return $this->deemedSupplierIn($country, $on)
            ? MarketplaceLiability::PlatformOwes
            : MarketplaceLiability::SellerCollects;
    }
});

The engine takes your answer for the place and the date; everything else — the rate, the treatment, the reporting — carries on as before.

The date matters

The check runs on the supply's date, not today's. A Missouri sale from 2022 predates that state's marketplace act and is still the seller's to collect; answering from today's map would zero a charge that was really owed. Pass suppliedAt on anything you reprice.

It runs before nexus

The platform's liability is not derived from the seller's presence, so the check runs before the seller's own registration. A seller with no nexus in the state still owes nothing on a facilitated sale — and the treatment says why, where NotRegistered would have said something else entirely about the same zero.

See marketplace facilitator for the full outcome table.