International Sports Office (ISO)
Balkan-to-Elite Bridge

Serbia

€65mm

Key Facts

Also known as: ISO; International Sports Office
Founded: 2015 (Serbia)
Headquarters: Zmaj Jovina 15, 11100 Belgrade, Serbia
Players: 23 (19 in 1st tiers) • Total market value: €65mm
FIFA/FA registration: FIFA-licensed agents on staff — Darko Ristic (Executive Director); Dejan Grgic (licensed). Operates under FFAR and Serbian FA (FSS) rules.
Languages: Serbian; English; French
Regions covered: Balkans; Central/Eastern Europe; Italy; Israel; Austria/Germany; North America (MLS/Mexico)
Email: office@isoffice.rs
Instagram: https://www.instagram.com/isoffice.rs
Facebook: https://www.facebook.com/InternationalSportsOffice

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About

International Sports Office is a Belgrade-based football agency founded in 2015. ISO blends elite representation with pathway development, combining hands-on career planning, strong club relationships and full off-field support. The agency rose to wider prominence with the marquee Dušan Vlahović transfer in January 2022 and today manages both top-flight internationals and high-upside prospects, plus selected coaches.

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Key People

• CEO/Founder: Dejan Grgic (co-founder)

• Managing Director / Head of Football: Darko Ristic — Executive Director

• Licensed agents: Darko Ristic; Dejan Grgic

• Senior staff: Nenad Bizic — Head of Scouting; Ognjen Ivanovic — Agent; Borisav Djokic — Recruitment/Scout

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Client Roster (teams in brackets)

Top players (current):

• Dušan Vlahović (Juventus FC)

• Veljko Birmančević (AC Sparta Prague)

• Dejan Joveljić (Sporting Kansas City)

• Svetozar Marković (FC Viktoria Plzeň)

• Kristijan Belić (Maccabi Tel Aviv)

• Bojan Kovačević (Cádiz CF)

• Uroš Đurđević (Atlas Guadalajara)

Rising talents / U23:

• Erik Kojzek (Wolfsberger AC)

• Jovan Sljivić (Red Star Belgrade)

• Mateja Đorđević (Austin FC)

• Mateja Milovanović (FK Partizan Belgrade)

• Aleks Zeković (Feyenoord U21)

• Andrej Kostić (FK Partizan Belgrade)

Notable former clients: not publicly documented

Coaches/Staff represented (if any):

• Dejan Stanković — Manager (Spartak Moscow)

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Notable Deals

• 2022 — Dušan Vlahović: Fiorentina → Juventus; permanent; ~€81.6m + bonuses; contract to 2026

• 2025 — Dejan Joveljić: LA Galaxy → Sporting Kansas City; cash trade ($4m); Designated Player deal to 2028

• 2025 — Bojan Kovačević: Cádiz CF activates purchase clause from Partizan; permanent; contract to 2029

• 2024 — Veljko Birmančević: Toulouse (end of loan) → AC Sparta Prague; permanent; ~€2.3m; contract to 2027

• 2024 — Svetozar Marković: Partizan Belgrade → FC Viktoria Plzeň; permanent; three-year deal

• 2025 — Kristijan Belić: AZ Alkmaar → Maccabi Tel Aviv; season-long deal to 2026

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Services

Contract negotiation; domestic & international transfers/loans; image rights and sponsorships; PR/branding and media; legal/tax liaison; relocation and family support; performance planning and long-term career strategy.

Partner Network

Representative club footprint includes Juventus, AC Sparta Prague, FC Viktoria Plzeň, Maccabi Tel Aviv, Maccabi Haifa, Cádiz CF, Legia Warszawa, Austin FC, Atlas Guadalajara, Wolfsberger AC, Red Star Belgrade, FK Partizan; allied scouts, lawyers, physios and marketing partners across Europe, Israel and North America.

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Track Record (last 3 seasons)

• Total transfers completed: 8+

• Deals ≥ €10m: 0 (within this period)

• Clients in top-5 leagues: 2 (Serie A; LaLiga)

• National team clients: Serbia (senior/youth); Montenegro; Bosnia & Herzegovina (youth)

• Renewal/extension deals: not publicly highlighted

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Approach & Philosophy

ISO is relationship-driven and scouting-led, prioritising playing time and role fit before step moves. Negotiations focus on value-protective structures (sell-ons, buy options, performance add-ons), while 360° player care — legal, financial and family support — de-risks relocations and sustains long-term development.

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Fees & Transparency

Commission ranges not publicly disclosed. Operates under FFAR and FSS regulations with written mandates; dual representation only with informed consent. Image-rights and reimbursable expenses handled case-by-case with prior approval.

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Compliance & Reputation

• Disciplinary actions / sanctions: none publicly reported

• Litigation / disputes: none notable in the public domain

• Media sentiment: positive/neutral — anchored by the Vlahović deal and steady top-flight placements