The commodity monitoring data for August 28 presents a telling picture: raw silk jumped 2.67% in a single day, leading the textile sector, while PTA and cotton rose modestly by 0.59% and 0.51%, respectively, with all other dozen-plus products flat. On the surface, this is just price fluctuation, but combined with year-on-year data, a structural divergence is brewing.
The Logic Behind Price Movements
Raw silk rose from 416,400 yuan/ton to 427,500 yuan/ton, setting a recent record for daily gain, yet still down 9.16% year-on-year. This suggests the rebound is more of an oversold correction than a trend reversal. For silk reeling enterprises and fabric buyers, the low base and short-term volatility may offer a window for phased inventory building.
Meanwhile, PTA is up 26.54% year-on-year, cotton up 19.12%, and acrylonitrile up a staggering 44.12%. The strength in chemical fiber raw materials contrasts sharply with the weakness in natural fibers. Polyester filament series (POY, DTY, FDY) all rose over 21% year-on-year, and nylon series gained 14-21%, reflecting accelerating cost transmission along the petrochemical downstream chain.
Notably, except for raw silk, PTA, and cotton, all other products were flat on the day. This 'three up, rest flat' pattern indicates that the market is not broadly heating up; instead, capital and demand are selectively focusing. Viscose staple fiber is up 10.43% year-on-year and spandex up 21.65%, but both were flat on the day, suggesting they are consolidating at high levels, awaiting new drivers.
Chain Transmission and Procurement Adjustments
From a chain perspective, the rise in PTA directly increases polyester production costs, but polyester staple fiber and yarn did not follow on the day, with moderate year-on-year gains (17.93% and 5.90%). This means upstream increases have not fully transmitted downstream, squeezing weaving mills. For factories relying on polyester, now may be a window to lock in long-term contract prices to avoid further cost escalation.
The raw silk anomaly should be viewed in the context of the silkworm cocoon supply cycle. Late August precedes the autumn cocoon market, making output expectations sensitive. The nearly 10% year-on-year drop indicates ample supply earlier, but the sharp daily rise may reflect short-term buying sentiment. For silk exporters, exchange rates and overseas demand remain dominant; price fluctuations mainly affect inventory valuation.
Cotton yarn 21S and 32S were flat on the day, with year-on-year gains of only 5.89% and 5.63%, significantly weaker than cotton's 19.12%. The lag in cotton yarn price transmission implies squeezed spinning margins. For buyers, cotton yarn prices are relatively stable, but watch for late-stage catch-up risk if cotton continues to strengthen.