Why is Norsk Hydro stock sliding today?

Recent market activity shows a downward trend for three specific companies. Norsk Hydro is experiencing a stock slide, reflecting current market pressures. Simultaneously, Seagate Technology is seeing its share price decline. Western Digital is also facing a similar slide in its stock value. These three entities are all witnessing a decrease in their market valuation today, as reported across multiple sources, indicating a period of volatility for these specific industrial and technology sector stocks.