YOFC (06869) shares plummeted 5.17% in intraday trading on Friday, continuing a downward trend that has seen the stock lose over 40% of its value since September highs. The sharp decline comes as the company faces multiple challenges in its core fiber optic business and experiences significant changes in its shareholder structure.

According to recent reports, Nomura has downgraded YOFC from "Buy" to "Neutral" following China Mobile's latest fiber optic tender results. The tender revealed a decline in both market share and average selling price for YOFC, which is expected to put pressure on the company's profits starting from the third quarter of this year. This development has raised concerns about YOFC's competitive position in the fiber optic market and its potential impact on future earnings.

Adding to the downward pressure, YOFC has experienced a significant change in its shareholder structure. On September 19, Draka Comteq B.V., previously one of the joint largest shareholders, sold its remaining 5% stake in YOFC through a block trade of 37.5953 million H shares. This move marks the complete exit of Draka Comteq B.V., which had been steadily reducing its holdings since April. The substantial sell-off by a major shareholder has likely contributed to investor uncertainty and the stock's continued decline.