Summary

  • American Tower consolidates its controlled U.S. data-centre business, so CoreSite’s whole US$586.0mn of first-half 2026 segment revenue appears in the group numbers. Consolidation establishes the reporting perimeter; it does not give American Tower 100% of the economics.
  • At 30 June, American Tower owned about 71% of the common equity, while Stonepeak owned about 29% plus all of the mandatorily convertible preferred equity. On the disclosed fully converted basis, expected in August and subject to a conversion-date adjustment, the interests would be approximately 64% and 36%.
  • CoreSite produced US$308.9mn of segment operating profit while using US$341.3mn of capital expenditure in the half. Those measures cannot be subtracted to manufacture free cash, but their proximity shows why operating growth, funding needs and partner distributions must be bridged before valuing the residual claim.

One platform produces three different percentages

American Tower’s second-quarter filing gives CoreSite the flattering part of the page. Data Centers revenue rose 13% in the quarter and 16% in the first half. Gross margin increased 19% over six months. Segment operating profit increased 18%. Management cited record leasing activity when it raised the group outlook.

The same filing places a less familiar percentage in a footnote. At the end of June, American Tower held approximately 71% of the common equity in its U.S. data-centre business. Stonepeak held approximately 29% of the common and all of the outstanding mandatorily convertible preferred equity. When that preferred converts, American Tower expected to own approximately 64% and Stonepeak approximately 36%, based on the equity then outstanding.

Both passages are true because they answer different questions. The segment table asks which operations American Tower controls and therefore consolidates. The ownership note asks who has the economic claim on the controlled business. Control can survive at 64%; full economic ownership does not.

That distinction becomes material precisely when CoreSite is growing. A weak segment can be dismissed as a small subsidiary. A fast-growing one invites investors to attach the full operating result to the listed parent. The correct bridge begins with 100% of the segment and ends with the cash and value attributable to American Tower common stockholders. It should not skip from one to the other.

The US$80mn increase has four sources

CoreSite’s first-half revenue rose from US$506.0mn to US$586.0mn. The filing decomposes the US$80.0mn increase rather than calling it simply AI demand. Rental, related and other revenue added US$46.0mn, mainly from new lease commencements, customer expansions and higher renewal rents. Power revenue contributed US$18.5mn through new commencements, greater consumption and pricing. Interconnection added US$7.9mn through net cross-connect additions and pricing. Straight-line accounting contributed US$7.6mn.

The mixture matters. New rent is a different signal from electricity resold to occupied halls; cross-connect growth is a different asset from a non-cash straight-line recognition. CoreSite’s interconnection position can deepen customer attachment because a tenant is buying access to clouds, carriers and counterparties, not merely a powered room. Power revenue can rise quickly, but the filing says utility costs also lifted direct expenses. Straight-line revenue improves the accounting period without becoming the same amount of current cash.

First-half gross margin rose from US$303.8mn to US$360.1mn, while segment operating profit rose from US$261.8mn to US$308.9mn. The gross-margin increase outpaced revenue, but SG&A climbed from US$42.0mn to US$51.2mn as personnel, legal and professional costs increased. This is strong operating performance, not a frictionless margin.

Thirty facilities in eleven U.S. markets sit behind the totals. CoreSite’s own footprint page describes more than 4.8mn square feet and direct links to the major cloud providers. Scale makes the segment legible. It does not make every dollar fungible.

Capital arrives before residual cash

Data Centers capital expenditure reached US$341.3mn in the first half, up from US$224.3mn a year earlier. It was US$32.4mn higher than segment operating profit. Full-year guidance included US$695mn of development spending for the segment.

The comparison is deliberately not a free-cash-flow calculation. Segment operating profit is an accrual measure before several group and ownership adjustments. Capital expenditure is a cash investment in long-lived assets and includes growth projects whose returns arrive later. Maintenance and development spending have different economics, and the filing does not supply a standalone CoreSite free-cash-flow reconciliation.

Yet the two lines belong on the same analyst’s page. A platform can report expanding operating profit while consuming more cash to create the next halls. If development is attractive, that outflow creates future rent and interconnection density. If power, construction or leasing slips, the same outflow delays the residual return. Revenue growth measures demand already entering the accounts. Capital expenditure measures how much more of the balance sheet is being committed before future demand pays.

This is where a capital partner changes the model. Stonepeak did not buy a footnote. It supplied approximately US$3.07bn in 2022 through common and preferred equity, after American Tower had completed the US$10.4bn CoreSite acquisition. The initial US$2.5bn and later US$570mn helped finance the purchase and repay debt. In exchange, Stonepeak obtained a present common interest, a preferred instrument accruing at 5% and a larger common claim after conversion.

The preferred coupon is a bridge, not a rounding error

During the first half of 2026, the U.S. data-centre business declared US$22.8mn of distributions on Stonepeak’s preferred equity; US$11.5mn remained accrued at quarter-end. It also declared and paid US$36.4mn of common distributions to American Tower and Stonepeak in proportion to their interests.

These figures should be kept separate. The US$22.8mn belongs to the preferred claim. The US$36.4mn is a common distribution pool shared under the ownership agreement. Adding them and calling the result “cash paid to Stonepeak” would overstate what the disclosure proves. Assigning the common pool entirely to American Tower would make the opposite mistake.

Conversion changes the form of the partner’s claim. The 5% preferred accrual ends under the disclosed schedule, while Stonepeak’s common percentage rises. That can simplify the capital structure without eliminating the minority interest. The final ratio was subject to an adjustment measured upon conversion, so 64% and 36% are expected endpoints, not integers to treat as completed facts before the transaction record confirms them.

The economic question after conversion is not whether American Tower still consolidates. At roughly 64%, it would remain the controlling owner on the disclosed facts. The question is how future cash is divided after the preferred coupon disappears and the common denominator changes.

Consolidation is a perimeter, not a promise

Under consolidation, American Tower reports all of the controlled business’s revenue, direct expense, assets, capex and segment operating profit. Non-controlling interests then enter the attribution of income, funds from operations and distributions. The group’s reported AFFO is explicitly “attributable to American Tower Corporation common stockholders” and adjusts for non-controlling interests. The filing does not provide an equally complete standalone bridge from CoreSite segment operating profit to AMT-attributable CoreSite cash.

This is why multiplying US$586mn by 64% is not an answer. It would allocate revenue before paying utility and other direct expenses. Multiplying US$308.9mn by 64% is still incomplete: segment operating profit is not cash available for distribution, and ownership agreements, financing, taxes, development capital and timing remain between the lines.

A more useful model starts with rental, power, interconnection and straight-line revenue separately. It deducts direct expense and segment SG&A, then separates maintenance from growth capex. It records debt and tax at the appropriate entity, the preferred accrual until conversion, common distributions by actual ownership date and any capital contributions. Only the residual can be allocated as a current cash claim.

The accounting perimeter tells investors where to look. The ownership waterfall tells them what they own.

Sources