Greenhill Lane

Greenhill Agency is an outsourced strategic advisory, marketing, and lifestyle services partner founded by Constance Costas. Drawing on more than 25 years of experience, the agency supports boutique investment firms, family offices, startups, and corporate marketing teams with senior-level expertise and discreet, flexible assistance. Its background includes work with Goldman Sachs, the NFL, and Citigroup Private Bank, alongside experience serving high-net-worth clients and managing projects across more than 40 countries.

The agency’s services span brand strategy, business development, strategic planning, partnerships, communications, and fractional Chief of Staff support. It also provides operational and administrative management, including board coordination, office management, investor tours, roadshows, and fundraising coordination. For client engagement, Greenhill develops and produces conferences, corporate retreats, fundraising events, sponsorship programs, and bespoke experiences.

Lifestyle services include tailored travel, private aviation and yacht coordination, luxury procurement, health and medical concierge support, property management liaison, and philanthropic initiatives. Greenhill combines a broad international network with hands-on coordination to help clients advance business priorities, strengthen their brand presence, and create memorable experiences with discretion.