This chapter traces how labelled green bonds moved from niche to systemic relevance, with issuance surging from USD 40 billion (2014) to over USD 550 billion (2023) and cumulative outstandings above USD 1.6 trillion. We document two pricing premia. First, a conditional “greenium” emerges in specific regimes and concentrates in ring-fenced, “dark-green” use of proceeds, with magnitudes shaped by liquidity, benchmark eligibility, disclosure credibility, and policy milestones (Paris Agreement, EU taxonomy acts, central-bank eligibility). Second, a Government Green Spread (public over private) widens counter-cyclically, reflecting benchmark-curve formation and flight-to-quality dynamics. Macro-financial frictions—exchange-rate volatility, capital-account constraints, and collateral policy—amplify or damp both premia, while local supply effects compress spreads until scarcity dissipates. A tranche-level study of 1389 European green bonds (2014–2021) shows rating as the dominant driver, an independent coupon-structure premium for floating-rate notes, and only limited size effects once sector is controlled; speculative-grade issuers do not enjoy a “green discount”. On regulation, we contrast the EU’s taxonomy-anchored EuGB framework and ESMA oversight with the U.S. reliance on principles and private certification, outlining gaps in standardisation, verification quality, and market readiness. The chapter closes with a research agenda on time-varying premia, primary-secondary linkages, cross-asset interactions, policy risk, digital market infrastructure, and measuring real-world additionality.