Direct Answer
NiSource reports revenue across 2 business segments in its fiscal 2025 Form 10-K. Columbia Operations is the largest, with $3.3 billion of revenue (51% of the total), followed by NIPSCO Operations at $3.2 billion (49%).
How Does NiSource Make Money?
No single line supplies a majority of revenue: the largest, Columbia Operations, is 51%, which spreads NiSource's exposure across several demand drivers. Between fiscal 2024 and 2025, Columbia Operations grew fastest (+26.5%) and NIPSCO Operations slowest (+20.5%), so the revenue mix tilts toward Columbia Operations while that gap lasts.
| Segment | FY2025 revenue | FY2024 revenue | Share of revenue | Change |
|---|---|---|---|---|
| Columbia Operations | $3.3 billion | $2.6 billion | 51.0% | 26.5% |
| NIPSCO Operations | $3.2 billion | $2.7 billion | 49.0% | 20.5% |
Which NiSource Segments Earn the Most?
| Segment | FY2025 segment operating income | Segment margin |
|---|---|---|
| Columbia Operations | $895 million | 26.9% |
| NIPSCO Operations | $938 million | 29.3% |
Segment operating income is the profit measure NiSource reports to its chief operating decision maker for each segment. It usually leaves out corporate costs that are not allocated to a segment, so the segments usually add up to more than consolidated operating income, and margins are comparable within NiSource more safely than against another company.
What the Segment Figures Do Not Show
The rows above add up to 100% of NiSource's reported revenue for fiscal 2025; the difference is intersegment eliminations, corporate revenue or items the company reports outside its segments. Segment definitions are management's choice and change when a company reorganizes, in which case it restates prior years in the next filing, so a multi-year comparison should use the figures from a single filing. Revenue shows where sales come from, not where profit or cash is earned: a small segment can carry most of the margin.
Where These Numbers Come From
Every figure on this page is a value NiSource reported in the segment note and revenue disclosures of its Form 10-K filed February 11, 2026 (accession 0001111711-26-000027), read from the SEC's Financial Statement Data Sets. The prior-year column is the comparative figure from that same filing, so it reflects any restatement for a change in segments. Category names are the company's own XBRL labels, lightly reformatted for reading.
Rows that only total other rows (for example a "Products" line beside the individual products) are left out so nothing is counted twice. This page is educational and describes reported history for fiscal 2025; it is not a forecast or a recommendation.
Frequently Asked Questions
What are NiSource's business segments?
In its fiscal 2025 Form 10-K, NiSource reports revenue for Columbia Operations and NIPSCO Operations.
Which part of NiSource brings in the most revenue?
Columbia Operations, with $3.3 billion of revenue in fiscal 2025, or 51% of the total.
Where does NiSource report its segment results?
In the segment note to the financial statements in its Form 10-K, most recently filed February 11, 2026, alongside management's discussion of each segment's results.