KB Home downgrade, Costco upgraded: Wall Street's top analyst calls

Group 1 - William Blair downgraded Dynavax (DVAX) to Market Perform from Outperform following Sanofi's announcement to acquire the company for $15.50 per share [1] - The acquisition is viewed as logical due to increasing regulatory concerns around vaccines and investor inquiries regarding management's strategy for value creation [1] - Alliance Global downgraded Spire Global (SPIR) to Neutral from Buy, reducing the price target from $17 to $9, pending evidence of recovery [1] Group 2 - Spire Global's management anticipates achieving positive operating cash flow by Q4 of 2026, which requires a 15% increase in Q4 of 2025 revenue estimates and $36 million in annual expense reductions [1] - Alliance Global considers the required financial improvements for Spire Global as "unlikely" [1]