St. Pauls Cathedral, left, and skyscrapers including, 30 St Mary Axe, also known as the 'Gherkin', center, the Leadenhall building, also known as the 'Cheesegrater', and 20 Fenchurch Street, also known as the 'Walkie-Talkie', stand beyond the River Thames in the City of London financial district, in London, U.K., on Monday, June 8, 2015. Job vacancies at Londons financial services companies jumped 52 percent last month with banks seeking more fixed-income traders as volatility in markets increased, according to a recruitment firm. Photographer: Jason Alden/Bloomberg via Getty Images