Trepp | Office Deals Led CMBS Growth Through July 2026, & Data Centers Arrived

Domestic private-label commercial mortgage-backed securities (CMBS) issuance reached $76.2 billion through July 2026, measured by loan balance when each deal was sold, according to Trepp data as of July 31.

Single-asset, single-borrower (SASB) deals, each backed by one property or one owner, made up $58.0 billion. Conduit deals, which pool many smaller loans from different owners, made up $16.1 billion. A small remainder came from large-loan deals. Office was the single largest property type at 22.7% of issuance, or $17.3 billion, ahead of industrial and multifamily at roughly 17.3% each.

Two features sit beneath that headline. First, the composition diverges sharply by channel: SASB issuance skewed toward office, industrial, and lodging, while conduit remained more heavily weighted toward multifamily and retail. Data centers appeared only in SASB deals.

Second, underwriting varies as much across property types as across those channels. Debt yield measures a property’s annual income as a percentage of its loan amount. On a loan-level basis, multifamily arrived with the thinnest debt yield of any major type at 8.20%.

It also carried the highest loan-to-value (LTV) ratio among the major types, at 68.4%. Lodging carried the widest debt yield at 12.69%. At maturity, debt yield can be a more useful constraint than DSCR because it measures property income against the full loan balance independent of the prevailing interest rate. On that measure, multifamily entered the market with the least cushion.

A Single-Borrower, Office-Led Year-to-Date

Office leads on an overall basis, but that ranking is a blend of two different books. In the single-borrower channel, office, industrial, and lodging together account for 62.1% of balance, the large, concentrated assets that define SASB execution. Data centers make the split clearest: they were 9.8% of SASB issuance and none of conduit issuance, so the sector reaches the securitized market only through single-borrower deals. Conduit stayed anchored in granular multifamily and retail collateral, which together were 35.5% of the conduit book against 22.9% of the SASB book.

Underwritten Debt Yield Separates the Property Types

The debt-yield range is the clearest differentiator between the underwriting practices across property types, with nearly 4.5 percentage points separating multifamily at 8.20% from lodging at 12.69%. Lodging’s wide debt yield reflects income that swings with the economy and depends on daily operations. Lenders typically require more income relative to loan proceeds to compensate for that risk.

Multifamily carries the thinnest debt yield, the highest LTV, and the lowest DSCR at 1.33x among the major types. That makes it the most aggressively underwritten major type of the year to date. That is not a performance problem today, but it is the smallest margin for error at refinancing if rates hold. Office and retail printed the lowest LTVs, near 59%, because lenders lent a smaller share of value against the large single-asset loans that anchor their issuance. Data-center figures rest on only five loans and should be read as concentrated rather than representative. Table 2 gives the full set.

2026 Underwriting Versus Recent Vintages

A vintage is the set of loans packaged into deals in a given year. The 2026 book carries a 63.0% overall LTV¹, the highest reading in Table 3 and up from a 54.0% trough in the 2023 vintage. Its 10.36% overall debt yield sits below the 11.86% of 2023 but above the 8.77% low of 2021, so income coverage is firmer than at the last cyclical peak even as leverage has returned. DSCR is the least comparable of the three across years: the 3.24x of the 2021 vintage reflects floating-rate single-borrower loans written at very low debt service, and it fell toward 1.5 to 1.7x as base rates rose. That instability across rate regimes is why debt yield, which is indifferent to the prevailing rate, is the steadier gauge, and on it the 2026 book looks better protected than 2021 and modestly behind 2023. Table 3 gives the series.

Within the 2026 book, the conduit channel underwrote more conservatively than the market as a whole on every metric, at a lower 58.5% LTV, a wider 13.20% debt yield, and a higher 1.89x DSCR. Conduit leverage, as measured by LTV, has notched a new post-pandemic high of 58.5%, above the 55.1% of 2021 and the 52.0% of 2023. Two cautionary signals sit alongside that firmer debt yield: leverage is at its highest in the table, and the average loan is interest-only for 93.4% of its term, weighted by balance. Little principal is repaid before maturity.

What the Year-to-Date Book Signals

The year-to-date data describe a market that is busy, concentrated, and better underwritten on income than the 2021 vintage, but more levered than the 2023 one. Three points follow. First, single-borrower collateral supplies more than three-quarters of the balance, so the overall figures mostly describe how those large deals were underwritten. The market’s resilience therefore depends on investor appetite for large office, industrial, and lodging assets.

Second, data centers have become a distinct single-borrower category, absent from conduit entirely, and they hold a 7.5% overall share.

Third, multifamily is the property type to watch on refinance risk. Among the major sectors, it has the largest presence in the conduit book, and it carries both the thinnest debt yield and the lowest coverage at securitization, so a soft patch in rents or values would compress its cushion first. The year-to-date book is strong on volume; the risk sits in the leverage and the light principal repayment beneath a debt yield that still looks healthy.

¹Conduit loans provide a more indicative signal of CMBS market underwriting trends than SASB loans due to SASB reflecting concentrated individual property characteristics