Stack rationalisation: an executive brief

A typical mid-market or enterprise company in 2026 runs 60–120 distinct SaaS tools. Of those, 15–25 are load-bearing (genuinely critical to operations); 25–40 are useful (add real value but are replaceable); and 20–60 are vestigial (signed for a project that ended, used by a team that left, or duplicating capability available elsewhere in the stack).

Stack rationalisation is the discipline of removing the vestigial tier and consolidating the useful tier without breaking workflows. It is not a glamorous initiative. It is also one of the highest-ROI exercises an executive team can run.

Why this matters now

Three reasons the conversation has accelerated in 2024–2026:

1. SaaS pricing has compounded faster than SaaS adoption rates. The average per-tool cost has risen ~40% over three years; the number of tools per organisation has stayed roughly flat. The combined bill is up materially, with no corresponding increase in capability.
2. AI tool sprawl has begun. Every department has bought one or two AI tools. Most are not yet load-bearing. The rationalisation conversation is best had before they become load-bearing.
3. Board scrutiny on operating leverage has tightened. Public-company and PE-backed boards are increasingly asking pointed questions about technology spend per employee. The answer “we have a lot of tools” no longer suffices.

The rationalisation framework

A clean stack rationalisation engagement has four phases:

1. Inventory. What tools does the organisation actually have? This is harder than it sounds. The procurement system has a list; the actual list is bigger (corporate-card subscriptions, departmental tools, free-tier deployments that have grown). We typically find 20–30% more tools than the procurement system knows about.

2. Classification. For each tool: is it load-bearing, useful, or vestigial? Who owns it? What does it cost? When does it renew? What capability does it provide that other tools in the stack don’t?

3. Decision. For vestigial: cancel. For useful: keep, consolidate, or rebuild. For load-bearing: keep (with the per-seat math conversation reserved for separate Upstream engagements).

4. Execution. Cancellations are easy. Consolidations require migration. Rebuilds (of load-bearing or useful tools) are full Upstream engagements, scoped separately.

The first three phases together are typically 4–6 weeks of work for a 60–120 tool stack. We ship this as a Strategy engagement.

What the executive brief looks like

The deliverable is a 20–35 page written brief with:

• Executive summary (1 page): how many tools, total annualised cost, recommended cancellations / consolidations / rebuilds, projected annualised savings.
• Inventory table (5–10 pages): every tool with classification, owner, cost, renewal date, recommended action.
• Recommended actions per tool (10–20 pages): for each non-trivial decision, the specific recommendation with the rationale.
• Implementation plan (3–5 pages): the order of operations to capture the savings, with dependencies and timing.
• Appendices: the consolidation patterns we recommend most often, the rebuild candidates that warrant separate Upstream evaluation.

The brief is yours. If you want to execute it without us, you should be able to take it to a different vendor and get a quote on the rebuild work.

Typical findings

Across the 12+ stack rationalisation engagements we’ve shipped:

• 15–25% of total SaaS spend is in the vestigial tier. Cancellable with no operational impact, often within 90 days.
• Another 10–20% is in the consolidate tier. Workflows can be migrated to existing tools, with savings that pay for the migration in 6–12 months.
• Another 10–25% is in the rebuild candidate tier. Where the rebuild math works (typically tools above $200K/yr), the Upstream engagement produces additional 70–90% reduction on the rebuilt categories.

Combined, a typical stack rationalisation produces 30–50% reduction in total SaaS spend within 12–18 months of the brief landing on the executive’s desk. The reduction compounds annually.

Where this work goes wrong

Two failure patterns we see:

1. The brief lands and nothing happens. Without an executive sponsor who owns execution, the brief becomes a shelved artefact. The most successful engagements have a named accountable executive (often the CFO or COO) who owns the cancellation calendar and reports progress quarterly.
2. The brief gets debated rather than executed. Each tool owner defends their tool. The rationalisation stalls. The cure is a pre-agreed decision framework: tools with no measurable usage in 90 days are cancelled by default; tool owners can object but must defend with evidence. This shifts the burden of proof in the right direction.

The brief itself is not the bottleneck. Execution is.

When to commission

The natural triggers for a stack rationalisation brief:

1. A new CFO or COO arrives and wants a baseline view.
2. A renewal cluster (multiple major contracts up for renewal in a quarter) creates leverage.
3. A board mandate to improve operating leverage.
4. A merger or acquisition that doubles the tool count.

In all four cases, the 4–6 week brief is a small investment relative to the annualised reduction it enables.

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