UK organisations buying Microsoft licences in 2026 navigate four programmes: Enterprise Agreement (EA), Cloud Solution Provider (CSP), Microsoft Customer Agreement (MCA-E direct), and the legacy MPSA / Open programmes (mostly retired). Picking the right one shapes 3-year cost by 15-30%.
The four programmes in plain terms
Enterprise Agreement (EA): 3-year commitment, minimum 500 users typical, organisation-wide standardisation, predictable price (with 5-10% annual escalator). Best for large enterprise with stable seat counts.
Cloud Solution Provider (CSP): partner-billed, monthly or annual, no minimum seat count, flex up/down per month. Best for small-mid market or organisations with variable seat counts.
Microsoft Customer Agreement (MCA-E direct): direct from Microsoft, replaces EA for some customers. Mid-market sweet spot 250-2,500 users. Annual or 3-year terms.
Legacy MPSA / Open Value: mostly retired. Migrate to CSP or MCA-E at renewal.
When to pick CSP
Under 500 users — EA minimum doesn't apply.
Want monthly flex — seasonal businesses, project-based teams, M&A activity.
Want UK partner billing relationship (single invoice covering Microsoft + other services).
Most UK mid-market (100-1,500 users) sits here.
When to pick EA
500+ users with stable seat count.
Want organisation-wide pricing standardisation across 3 years.
Comfortable with 5-10% annual escalator + 3-year commitment.
Have Software Assurance benefits (training vouchers, planning services) that you actually use.
When to pick MCA-E direct
250-2,500 users — too small for traditional EA but bigger than typical CSP.
Want direct Microsoft relationship for some workloads but partner support for others.
Consolidating multiple existing EA / CSP arrangements.
Per-licence price drivers
Volume tier — higher seat count = lower per-licence cost.
Term length — 3-year commitment cheaper than 1-year.
Programme — CSP typically 5-15% premium vs equivalent EA; EA typically 5-15% premium vs MCA-E direct list.
Promotions — quarterly promotions (M365 E5 upgrade discount, Azure migration credits, GitHub Copilot bundling) change the maths.
Negotiation — large EA / MCA-E renewals routinely 5-20% off list with right reseller advocacy.
What Servnet does
Servnet is a Microsoft CSP partner + EA / MCA-E advisor. We can sell + service all programmes, and we're honest when one isn't right. We pair the licensing motion with Entra ID hardening and Defender for Endpoint where customers consolidate to M365 E5.
For renewals: 1) entitlement audit, 2) SAM review for over-licensing waste, 3) sized commercial comparison across applicable programmes, 4) renewal negotiation + signing. Bundle with tenant consolidation if you're carrying multiple tenants from M&A activity, and read our UK reseller framework for partner-selection criteria.