美国至6月4日8周国债竞拍-得标利率配置百分比 68.26%，前值82.33%。

Prices for A2-class high-end fiber preforms — the upstream rods that determine optical-fiber performance — have surged, rising from 22–30 yuan per equivalent core-km in early 2025 to about 160 yuan per equivalent core-km in 2026, an increase of nearly 550%. Preforms account for roughly 70% of profit allocation in China’s fiber-cable value chain. A2 preforms produce bend-insensitive fiber widely used in AI compute infrastructure and last-mile/FTTH deployments, driving current demand. Capacity expansion typically requires 18–24 months, so supply tightness is likely to persist in phases; firms with existing preform capacity are positioned as the main beneficiaries, while smaller manufacturers may face supply shortages, subcontracting and margin compression.

房利美股价升至盘中高点5.5%。