When Brent crude settles above $100 a barrel, the most immediate reaction in textile raw materials is not in oil itself, but in the price ratio between polyester and cotton. ICE December cotton closed up 1.11% at 87.28 cents/lb, rebounding from the previous session's three-week low of 85.56 cents/lb. The driver behind this rally is not stronger demand, but passive support from rising substitute costs.
The Price Ratio Logic: How Oil Transmits to Cotton Valuation
PTA and MEG, the core feedstocks for polyester, are both oil derivatives. Every step up in crude lifts the cash cost of polyester staple fiber and filament yarn. When oil breaks $100, polyester's relative price advantage narrows, prompting spinning mills and fabric makers to adjust their fiber blend ratios. This means cotton's demand substitution effect stems not from end-consumer recovery, but from a structural shift forced by feedstock costs.
Meanwhile, the dollar index retreated to a near two-week low, making dollar-denominated cotton cheaper for overseas buyers. For export-oriented spinning enterprises, the aligned effect of currency and oil provides dual bottom support for international cotton prices in the short term. However, the sustainability of this support depends on Middle East developments, not industry fundamentals.
Supply Side: U.S. Quality Decline vs. Brazilian Output Growth
USDA's weekly crop progress report shows U.S. cotton good-to-excellent ratings fell to 34% as of September 6, down from 39% the prior week and 54% a year earlier. The harvest rate stood at 7%, matching last year and slightly above the five-year average of 6%. The sharp downgrade in quality ratings suggests a narrower share of high-grade U.S. cotton this season, creating structural constraints on supply for fine-count and combed yarn users.
But the Southern Hemisphere offers a counterweight. Consultancy Agroconsult raised its 2025/26 Brazilian lint cotton production forecast by about 300,000 tonnes to a record 4.5 million tonnes, citing improved yields from field surveys. Brazil's continued output growth is reshaping global cotton trade flows, particularly affecting Asian buyers' sourcing mixes—when high-grade Australian and U.S. resources tighten, Brazilian cotton's substitutability strengthens markedly.
On inventories, ICE deliverable No. 2 cotton stocks held steady at 54,414 bales, a relatively low absolute level that poses no immediate pressure on near-month contracts. The Cotlook A Index stood at 96.10 cents/lb, up 10 points, with spot market gains modest, indicating physical buying has yet to fully follow.
Industry Impact: The Cost-Rhythm Game for Textile Enterprises
For domestic spinning mills, the core contradiction is clear: feedstock cost expectations are rising, but downstream grey fabric and garment orders have limited capacity to pass through price increases. The polyester substitution effect from higher oil prices is short-term positive for cotton consumption, but if end demand fails to improve in tandem, mills will face a squeeze from both feedstock and finished product sides.
From a regional perspective, chemical fiber fabric clusters like Keqiao and Shengze are more sensitive to oil prices, with polyester feedstock volatility directly reflected in fabric quotes and order negotiations. Meanwhile, cotton-spinning regions such as Nantong and Foshan focus more on domestic-international cotton price spreads and quota policy changes. Sourcing strategies across industrial belts are diverging.
The next key market node is USDA's global agricultural supply and demand estimate report due Friday. Traders will use it to gauge Northern Hemisphere harvest supply节奏 and price direction. Before the report lands, cotton prices will likely remain range-bound, with the tug-of-war between support and resistance levels continuing.