What is a free cash flow bridge?

A free cash flow bridge (FCF bridge) is a period-over-period reconciliation that decomposes the change in free cash flow into its two primary drivers: the change in operating cash flow and the change in capital expenditure. Each bar shows the signed contribution of that driver to the total FCF change, and the drivers add up exactly to the FCF movement from one period to the next.

How is the OCF/Capex split of blame calculated?

The FCF identity is: ΔFCF = ΔOperating CF + ΔCapex. A positive ΔOperating CF bar means the business generated more operating cash — this adds to FCF. ΔCapex is the change in capital expenditure (stored as a negative outflow in reported figures), so a capex increase (more spending) produces a negative bar that reduces FCF. A residual "Other Items" step only appears when the reported free cash flow figure differs from operating CF minus capex.

What is FCF conversion and why does it matter?

FCF conversion is the ratio of free cash flow to operating cash flow (FCF ÷ OCF). A ratio above 80% indicates that most operating cash is retained as free cash after capital investment. The bridge snapshot shows the period-over-period change in this ratio in percentage points, so you can quickly see whether capital efficiency improved or deteriorated.

How is the prior period selected?

For TTM, the prior period is the trailing twelve months ending one year earlier. For fiscal years, it is the immediately preceding fiscal year. For quarters, it is the same quarter one year earlier (year-over-year). Periods without a comparable prior period are excluded from the bridge period dropdown, so the chart is always available for the selected period.

What does the capex sign convention mean?

Capex is recorded as a negative number in cash flow statements because it is an outflow. On the FCF bridge, a bar labelled "Capital Expenditure" that points downward means capex spending increased — the company invested more, which reduced free cash flow. A bar pointing upward means capex declined, releasing cash and lifting FCF. The magnitude of the bar is always the period-over-period change in capex (not the capex level itself).

How can operating cash flow rise while free cash flow falls?

This happens when capex increases more than operating cash flow improves. For example, if OCF grows by $200M but capex rises by $400M, FCF falls by $200M despite the operating improvement. The bridge makes this visible: the positive OCF bar is more than offset by the negative capex bar. This pattern is common during heavy investment cycles, acquisitions-light growth, or major infrastructure builds.

What drove Alnylam Pharmaceuticals (ALNY) free cash flow change vs TTM through Q1 2025?

Alnylam Pharmaceuticals's free cash flow increased by $717M versus TTM through Q1 2025. The bridge above decomposes that change into operating cash flow and capex contributions so each driver's contribution is visible and the total reconciles exactly to the reported change.

Alnylam Pharmaceuticals (ALNY) Free Cash Flow Bridge

FCF YoY

+950.75%

OCF YoY

+1,680.32%

Capex YoY

+136.37%

FCF Conversion Δ

-77.1 pp

Free cash flow bridge for Alnylam Pharmaceuticals (ALNY) — TTM through Q1 2026 vs TTM through Q1 2025

Δ Free cash flow: $717M

FCF bridge breakdown for Alnylam Pharmaceuticals (ALNY) — TTM through Q1 2026 vs TTM through Q1 2025

Driver	Contribution	% of Δ
Prior Free Cash Flow	-$75.4M	—
Operating Cash Flow	$758M	+105.8%
Capital Expenditure	-$41.3M	-5.8%
Free Cash Flow	$641M	—

Prior Free Cash Flow-$75.4M
Operating Cash Flow$758M
Capital Expenditure-$41.3M
Free Cash Flow$641M

Identity check: drivers reconcile to ΔNI within $0.00 ✓

Want to see how cash flow is built up?Cash Flow Waterfall

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Free cash flow bridge for Alnylam Pharmaceuticals (ALNY) — TTM through Q1 2026 vs TTM through Q1 2025

FCF bridge breakdown for Alnylam Pharmaceuticals (ALNY) — TTM through Q1 2026 vs TTM through Q1 2025

Frequently asked questions

What is a free cash flow bridge?

How is the OCF/Capex split of blame calculated?

What is FCF conversion and why does it matter?

How is the prior period selected?

What does the capex sign convention mean?

How can operating cash flow rise while free cash flow falls?

What drove Alnylam Pharmaceuticals (ALNY) free cash flow change vs TTM through Q1 2025?

Data & methodology

What is this view?

How is the FCF bridge calculated?

What is the sign convention?

How is the prior period selected?

Alnylam Pharmaceuticals (ALNY) Key Financials

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