Biotechnology companies like Annexon, which are in clinical stages, are highly sensitive to the availability and cost of capital. Rising interest rates and tighter credit markets could increase the expense of funding crucial research and development, potentially slowing pipeline progression and increasing dilutive financing activities.

Broader economic uncertainty, such as that caused by ongoing geopolitical conflicts (like in the Middle East) and downgraded global growth forecasts, can lead to decreased investor appetite for riskier assets. As a pre-revenue biotech firm, Annexon may face reduced investment and higher volatility during periods of market apprehension.

The regulatory environment, including decisions from agencies like the FDA for drug approvals and general healthcare policy, is a critical macro factor. Favorable or unfavorable shifts in these policies can significantly impact the commercial viability and market access for Annexon's pipeline products, particularly given its focus on complex neurodegenerative and autoimmune diseases.