US equity markets rallied, logging a broad advance in the final hour of the session - Dow rallied +478-points or +1.22%, and is on pace for its best first quarter gain since 2021. Merck & Co rallied +4.96% to be the leading component in the 30-stock index a day after the U.S. Food and Drug Administration (FDA) approved its drug (which will be marketed as Winrevair)  to treat a rare, progressive and life-threatening lung condition called pulmonary arterial hypertension.