Teapots are China's independent refiners, concentrated in Shandong province. The name is dismissive and outdated: the sector includes large, modern, complex plants alongside genuinely small simple ones, and in aggregate it accounts for a substantial share of national refining capacity.
What matters about them is behavioural rather than technical. Independents run on commercial margin with limited balance sheet cushion, so they cut runs quickly when cracks compress and raise them quickly when cracks recover. State-owned refiners have throughput obligations, product supply responsibilities and access to cheaper capital, so they run through weak margins that would shut an independent. The two respond to the same price signal on different timescales and with different amplitudes.
That makes the independent sector the marginal buyer of crude in a large part of the market, which is exactly the position that determines price at the margin. When teapot utilisation falls, seaborne crude demand falls with it, and it falls faster than a national average run rate would suggest.
Their crude preference is also specific and matters for differentials. Independents have historically favoured discounted heavy and sour grades, because their economics depend on buying cheap feedstock rather than on optimising a product slate. So the sector's activity level is a live input into the sour crude differential, and a teapot run cut widens heavy sour discounts more than it moves light sweet ones.
The sector is also subject to administrative intervention in a way commercial refiners elsewhere are not. Crude import quotas are allocated to independents, tax enforcement has been tightened periodically, and capacity consolidation has been pursued as policy. Those interventions can change the sector's behaviour abruptly and for reasons entirely outside the price signal.