Moderna shares slip as William Blair cuts rating on valuation after rally

Investing.com -- Moderna Inc (NASDAQ:MRNA) slid 3% in premarket trading after William Blair downgraded the biotechnology company to Market Perform from Outperform, citing valuation constraints following a meteoric run. The downgrade follows a staggering 545% year-to-date rally, driven by a near-250% surge since August after encouraging Phase 3 INTERPATH-001 data for its personalized cancer vaccine candidate.