A single US federal agency, the Department of Health and Human Services, manages a budget larger than the entire GDP of the Netherlands. Scale like that is why "the public sector" is not one market: it is dozens of overlapping ones, and knowing which layer you are selling into, regulating, or benchmarking against changes everything about how you size an opportunity.
This lesson gives you the numbers, the vocabulary, and the quick math to orient yourself in minutes rather than weeks.
The US: roughly $6 trillion, three layers
US government spending across all levels is commonly estimated at around $9-10 trillion per year on a total-expenditure basis (federal + state + local, gross), but a more usable "market size" figure that analysts often cite for federal government spending alone is roughly $6-6.5 trillion in annual outlays (estimate, FY2024/2025 basis, Congressional Budget Office). Treat any single headline number with caution: it depends heavily on whether you count gross outlays, net of transfers, or GDP share (federal spending is roughly 22-24% of US GDP as an estimate).
The three layers you must distinguish:
Federal: national government. Departments (HHS, DoD, DHS) and agencies (IRS, NASA). Sets national policy, defense, entitlements (Social Security, Medicare).
State: 50 states, each with its own budget, procurement rules, and agencies. State budgets collectively run into the trillions; California's state budget alone is larger than most European countries' entire national budgets (estimate, over $300B annually).
Local: roughly 90,000 local government units in the US (estimate, per US Census Bureau), counties, cities, school districts, special districts (water, transit). Fragmented, but collectively significant: local government spending is a similar order of magnitude to state spending.
Quick math: if a vendor claims "20% of US federal IT spending," and federal IT spending is estimated around $100-110B/year (estimate, per OMB IT Dashboard figures), that claim implies roughly $20-22B in revenue. If the company reports $2B in actual public sector revenue, the claim is almost certainly overstated, or scoped to a narrow sub-segment (e.g., just cybersecurity, not all IT).
Europe: fragmented by design, harder to size in one number
There is no single "European public sector market" the way there is a US federal budget, because Europe stacks three governance layers that do not nest neatly:
EU level: the European Union's own budget (the Multiannual Financial Framework, MFF) is modest by comparison, roughly €1.2 trillion over seven years (2021-2027, estimate, per European Commission), so around €170B/year. This mostly funds cohesion, agriculture (CAP, Common Agricultural Policy), and research (Horizon Europe). The EU does not run hospitals or police forces; member states do.
National level: each of the 27 EU member states (plus UK, Norway, Switzerland as non-EU Europe) runs its own budget. Aggregate general government expenditure across the EU is commonly estimated at over €7 trillion/year (estimate, per Eurostat), which is why "€2T+" undersells it if you include all spending categories; €2T+ is closer to a conservative estimate of *addressable* (non-transfer, procurable) public spending.
Municipal/regional level: cities, regions (Länder in Germany, régions in France, comunidades autónomas in Spain). Fiscal power varies enormously: German Länder have real tax-raising authority; French regions mostly execute national policy with delegated budgets.
Key distinction for sizing: EU general government expenditure as a share of GDP averages around 47-49% across member states (estimate, Eurostat), versus roughly 35-38% for total US government spending as a share of GDP (estimate). This is the single most important comparative benchmark: Europe's state footprint is structurally larger relative to its economy, even though the *EU institutions themselves* control a small slice of it.
Vocabulary and acronyms you need cold
RFP / RFQ / RFI: Request for Proposal / Quotation / Information, the standard procurement documents in both markets.
GSA Schedule: US General Services Administration's pre-approved vendor contract vehicle; a common entry point for selling to US federal agencies.
GovCon: shorthand for "government contractor," a US industry term.
TCV / ACV: Total Contract Value / Annual Contract Value, standard ways to size a public contract.
Procurement Directive: EU-level rules (Directive 2014/24/EU) setting thresholds above which public contracts must be competitively tendered EU-wide.
OJEU / TED: Official Journal of the EU / Tenders Electronic Daily, the EU-wide portal where above-threshold public tenders must be published.
PPP: Public-Private Partnership, a long-term contract where a private entity finances and operates public infrastructure (common in transport, hospitals).
NGEU: NextGenerationEU, the EU's roughly €800 billion pandemic recovery fund (2021-2026, estimate), a major one-off driver of European public investment.
SAM.gov: the US federal government's central vendor registration and contract-opportunity database.
The calculation professionals actually run
When someone says "Company X is a leader in European public sector cloud," don't take it at face value. Run this check:
1. Find the company's disclosed public sector or government revenue (annual report, investor deck).
2. Estimate the addressable market at the layer they claim (EU-wide vs. one country vs. one city).
3. Divide to sanity-check the implied share.
Worked example: A vendor claims €500M in "European public sector" revenue and says they hold "15% market sharemarket shareThe percentage of total industry sales your company captures in a given period. It measures competitive position relative to rivals in a defined market.View full definition →." That implies a total addressable markettotal addressable marketTotal Addressable Market: the total revenue opportunity if you captured 100% of potential customers in your target market.View full definition → of roughly €3.3B (€500M ÷ 0.15). If the actual European public sector IT spending is estimated at €120-140B/year (estimate, per IDC government ICT spending trackers), a €3.3B market would only be a narrow sub-segment (e.g., one country's cybersecurity spend), not "European public sector" broadly. Either the claim is scoped narrower than stated, or the share is inflated. This 60-second check separates marketing from reality.
Knowledge check
1. Why is it misleading to talk about 'the public sector' as a single market when sizing an opportunity?
2. A colleague cites '$9-10 trillion' as US government spending, while another cites '$6-6.5 trillion.' What most likely explains the discrepancy?
3. When would it be more appropriate to reference 'federal spending as a share of GDP' rather than a raw dollar figure?
MULTIPLE CHOICE
4. Select ALL correct answers about the distinction between federal, state, and local government layers in the US.
Select all the correct answers.
MULTIPLE CHOICE
5. Select ALL correct answers about why comparing a US state budget (e.g., California's) to a European national budget is a meaningful comparison.
Select all the correct answers.
Growth signals and benchmarks to watch
Digital transformation spending is the fastest-growing line in both markets: US federal civilian IT modernization and EU "digital decade" targets are pushing double-digit annual growth in gov-tech budgets (estimate, low-to-mid teens % YoY in cloud/cyber sub-segmentssegmentsDividing a market into distinct groups of customers who share similar needs, characteristics or behaviours, so each group can be served with a tailored approach.View full definition →).
Defense spending is a structural growth driver in Europe post-2022, with many NATO members moving toward or past the 2% of GDP NATO guideline (some now targeting higher, per NATO published figures), a material shift from the prior decade.
Aging population pressure: healthcare and pensions dominate both US (Medicare, Medicaid, Social Security are the largest entitlement lines) and EU national budgets, and are the primary reason total government spending as % of GDP keeps drifting upward, not down.
Due diligence checklist before you size anything
Always ask: gross or net spending? Federal-only or all-in? Fiscal year or calendar year?
Check the *layer*: EU institutional budget, national budget, or municipal budget are not interchangeable.
Verify currency and year on every figure; EU aggregates mix eurozone and non-euro members (UK, Poland, Sweden), which distorts euro-denominated totals over time.
Cross-check vendor claims against primary sources: USAspending.gov for US federal contract data, TED Europa for EU-wide tenders.
🎬 [VIDEO: "How the US Government Spends Your Money" - youtube.com - a visual breakdown of the US federal budget by department, useful for grounding the trillion-dollar figures in this lesson]
Key Takeaways
The US public sector is best sized in three layers (federal, state, local); federal outlays alone are estimated around $6-6.5T/year, but total government spending is closer to $9-10T (estimate).
Europe has no single market number: EU institutional spending is small (~€170B/year, estimate) while aggregate national spending across the EU exceeds €7T/year (estimate); "€2T+" typically refers to addressable/procurable spending, not total.
Government spending as % of GDP is a more reliable comparator than absolute dollars: roughly 47-49% in the EU versus 35-38% in the US (estimates).
Always sanity-check market-share claims by backing into implied total addressable markettotal addressable marketTotal Addressable Market: the total revenue opportunity if you captured 100% of potential customers in your target market.View full definition → and comparing it against independent trackers (IDC, Eurostat, CBO, USAspending.gov).
Structural growth drivers to watch: digital modernization budgets, European defense spending post-2022, and aging-population healthcare/pension costs on both sides of the Atlantic.