How a commercial mortgage becomes a CMBS bond, step by step

CMBS securitization pools commercial mortgages, sells them to a trust, and issues bonds backed by the loans’ payments. Lenders originate the loans, a depositor places them in a REMIC trust, rating agencies and the B-piece buyer review the pool, and underwriters sell the bonds. BANK5 2025-5YR14’s prospectus is dated April 1, 2025; the deal closed about April 24.

This page walks through each step using that deal’s filings: its prospectus and pooling and servicing agreement.

Step 1: Origination

A conduit lender makes a fixed-rate loan on stabilized income property and closes it on its own balance sheet. The rate is set at closing; the loan is written on the lender’s securitization forms so it can be sold. In BANK5 2025-5YR14 four banks sold loans into the deal: Wells Fargo Bank (9 loans, 45.1% of the pool), Morgan Stanley Mortgage Capital Holdings (10 loans, 34.9%), JPMorgan Chase Bank (3 loans, 9.5%) and Bank of America (2 loans, 4.8%), plus one loan, the Spiral, sold jointly by JPMorgan and Wells Fargo (5.8%).

For the borrower, this is the only step you take part in. Everything after it explains why the loan was underwritten and documented the way it was. How the lender sizes the loan is on CMBS underwriting.

Step 2: Aggregation and pool building

The lender holds loans until it has enough for a deal, then combines them with loans from other sellers. Large loans are often split into pari passu notes so that pieces can go into several deals; the Spiral’s $51 million note in this deal is one piece of a whole loan with $2.03 billion of other senior notes.

Step 3: The B-piece buyer re-underwrites the pool

Before the bonds price, the investor buying the first-loss classes reviews every loan. In this deal the prospectus says the B-piece buyer “was given the opportunity by the sponsors to perform due diligence on the mortgage loans” and “to request the removal, re-sizing or change in the expected repayment dates or other features of some or all of the mortgage loans,” and that “the mortgage pool as originally proposed by the sponsors was adjusted based on certain of these requests.” Federal risk retention rules require that review: a third-party purchaser must conduct “an independent review of the credit risk of each securitized asset” (17 CFR 246.7(b)(4)). See the B-piece and risk retention.

Step 4: Ratings

The depositor asks rating agencies for preliminary views, then hires some of them. In BANK5 2025-5YR14 the depositor “had initial discussions with and submitted certain materials to five NRSROs” and hired three (Fitch, KBRA and Moody’s), passing over the others “due, in part, to those NRSROs’ initial subordination levels.” Information given to the hired agencies is posted for the others under SEC Rule 17g-5, so they can issue unsolicited ratings. How the agencies work is on how CMBS bonds are rated.

Step 5: Documents and SEC disclosure

A public CMBS deal is registered on Form SF-3 (17 CFR 239.45). Shelf eligibility requires, among other things, a certification signed by the depositor’s chief executive officer for each offering and a transaction agreement that appoints an asset representations reviewer not affiliated with the sponsor, depositor, servicer or trustee. The depositor files loan-level data on Form ABS-EE under Schedule AL (Item 1125 of Regulation AB), and the PSA is filed on Form 8-K. Each loan seller signs a mortgage loan purchase agreement giving representations and warranties on its loans, with a duty to repurchase, substitute or pay for a loan that materially breaches them.

Step 6: Pricing and closing

Underwriters market the offered classes, set the coupons and prices, and the deal closes. In this deal seven underwriters sold $784,938,000 of offered certificates; the prospectus is dated April 1, 2025, delivery was expected on or about April 24, 2025, and the depositor expected to receive about 106.2% of the offered certificate balance, plus accrued interest, before expenses. The non-offered classes, including the first-loss classes, were sold privately.

Date	Event (BANK5 2025-5YR14)
April 2025	Cut-off date: each loan’s April 2025 payment due date
April 1, 2025	Prospectus date
April 2, 2025	Prospectus and PSA filed with the SEC
On or about April 24, 2025	Closing: loans transferred, certificates delivered
May 2025	First monthly distribution to bondholders
April 2058	Rated final distribution date

Step 7: Life of the trust

After closing, the trust is run under the pooling and servicing agreement. The master servicer collects payments and advances missed ones; loans in default move to the special servicer; the certificate administrator pays bondholders monthly and files distribution reports on Form 10-D, with updated loan-level data on Form ABS-EE. That public file is what powers CMBS loan rates, CMBS statistics and the special servicer directory on this site.

What the process means for a borrower

• Your terms are fixed before the bonds are sold, so a bad bond market after closing does not change your rate. Before closing, it can change your loan: lenders widen spreads or cut proceeds when the bonds are harder to sell.
• Your loan has to fit a pool. Standard documents, reserves and cash management exist because dozens of loans must be described, rated and sold together. See CMBS loan terms.
• After closing you deal with servicers. Your lender no longer owns the loan. See master vs special servicer and servicer consent.
• The tax wrapper limits changes. The trust is a REMIC, which constrains modifications and rules out adding money to the loan; extra proceeds come as supplemental financing.

Ready to start at step 1: how to get a CMBS loan and the CMBS loan checklist.

Sources: BANK5 2025-5YR14 prospectus (424B2): cover page, “Summary of Terms” (sponsors, loan sellers, relevant dates), “Potential Conflicts of Interest in the Selection of the Underlying Mortgage Loans”, “Ratings” and the related risk factor, “Description of the Mortgage Loan Purchase Agreements”; 17 CFR 239.45 (Form SF-3), 17 CFR 229.1125, 17 CFR 246.7, eCFR current text.