Why is Pfizer falling/rising?

As of 24-Sep, Pfizer Ltd. is experiencing a decline in its stock price, currently at 4,995.45, reflecting a decrease of 25.05 or 0.5%. The stock has been on a downward trend, losing 3.96% over the past week and 11.80% over the last month. Despite this, the stock is performing inline with its sector today, and there has been a notable increase in investor participation, with delivery volume rising by 11.09% against the 5-day average. The company boasts a high dividend yield of 3.29% and maintains a strong management efficiency with a return on equity of 18.22%. However, the stock's performance has been underwhelming compared to the benchmark, as it has fallen 4.92% year-to-date while the Sensex has gained 4.58%.
In the broader market context, Pfizer's recent performance contrasts sharply with the Sensex, which has shown a positive return of 0.50% over the past month and a significant 4.58% year-to-date increase. This disparity highlights the stock's struggle in a generally favorable market environment. While the company has a low debt-to-equity ratio and positive operational cash flow results, these factors have not been sufficient to counteract the recent price decline. The stock's performance over the past year has also been negative at -9.16%, compared to the Sensex's decline of only -3.77%, indicating that investor sentiment may be more cautious regarding Pfizer despite its solid fundamentals.