Kostis is the founder of AHUM Coaching for Transition providing Strategy & Org. Development Services through Team Coaching processes with an emphasis on co-creation.

The last 24 years Kostis has supported leadership teams in transition to co-create their Core Purpose, Vision and Values, define their key strategic directions and capitalize upon the richness of the diversity of their members and their collective strengths and aspirations. His expertise includes the support of individual executives in transition to new roles, organizations, countries or totally new careers.  
He has supported more than 30 organizations in the context of broader organizational development projects delivering more than 4000 hours of Executive & Team Coaching to senior executives and entrepreneurs across industries - global banks, insurance companies, media groups, telecommunications, pharmaceuticals, healthcare, intralogistics, food industry, HR Consulting, oil companies, digital media, advertisement agencies, exclusive design, art galleries and NGOs.

His clients include BP, Roche, White & Case LLP, Prudential, Credit Swiss, SocieteGeneral, Eurobank, McCann Worldgroup, GROWTHFUND, BIOIATRIKI, JUNGHEINRICH HELLAS, VALUECOM, ATTICA BANK, ANTENNA Group, Stanton Chase Athens, TITAN Cement, Adidas, Takeda, Adweb, Provil, Fresko,, ANAKTAE, Onside, Callista, yellowgroove, Skoufa Galleries, EASE, WWF, Action Aid, Greenpeace, Desmos, Metadrasi.

Kostis is member of the advisory boards of Desmos and The Power of a Flower