Government Contracts: SIGA Technologies' primary revenue stream comes from government contracts for its smallpox antiviral, Tpoxx. Contract size, renewal, and potential competition significantly impact stock price.

Public Health Emergencies: Outbreaks or perceived threats of smallpox or related orthopoxviruses (like monkeypox) can drive increased demand for Tpoxx, leading to surges in stock price.

Regulatory Approvals: Regulatory approvals in new geographies or for expanded uses of Tpoxx can positively affect the stock price. Conversely, delays or denials of approvals can have a negative impact.

Competition: The emergence of competing antiviral treatments or preventative measures for smallpox or related diseases could reduce demand for Tpoxx and negatively affect SIGA's stock price.

Financial Performance: SIGA's revenue, earnings, and cash flow reports influence investor sentiment. Strong financial performance typically boosts the stock price, while weak results can lead to a decline.

Market Sentiment: General market conditions and investor sentiment towards the biotechnology and pharmaceutical sectors can impact SIGA's stock price, regardless of the company's specific performance.

Supply Chain: Disruptions to SIGA's supply chain, potentially impacting the production and delivery of Tpoxx, could negatively affect the stock price.

Geopolitical Events: International tensions or political events that could increase the risk of bioterrorism or the use of smallpox as a weapon can lead to increased government stockpiling of Tpoxx, driving up the stock price.

Patent Protection: The strength and duration of SIGA's patent protection for Tpoxx are crucial. Challenges to or expiration of patents could lead to increased competition and lower prices.

Management Decisions: Strategic decisions made by SIGA's management, such as acquisitions, partnerships, or significant investments, can influence investor confidence and affect the stock price.