Babcock International paced the FTSE 100 gains, with shares climbing 6.8% to 11.08 pounds as the market reacted to the cabinet shift. BAE Systems followed with a 3.3% rise, while QinetiQ jumped 4.1% and Rolls-Royce added 1.9%. Analysts at J.P. Morgan signaled that Healey’s track record makes a push for higher defense budgets a near certainty.

Healey previously resigned from his post under former Prime Minister Keir Starmer, citing a frustration with the government's reluctance to commit more capital to the military. He has explicitly advocated for defense spending to reach 3% of GDP by 2030, outpacing the current 2.7% trajectory. The appointment by Prime Minister Andy Burnham also triggered a rally in European defense firms, with Italy’s Leonardo rising 3.8% and France’s Thales gaining 1.7% as investors accounted for their exposure to U.K. contracts.