Methodology
How the Deal Cost Index is built
Every figure is either disclosed in a public filing, listed on a vendor's price page, quoted from a published survey, or computed from a published formula — and each is labelled as such.
Nothing is scored or ranked. Tables are ordered by the numbers they contain. Calculator results are projections from these records, not quotes; see the terms and disclaimer.
About this site
Deal Cost Index is a reference site that estimates what a transaction costs in professional fees. Every figure is taken or projected from public sources — SEC and court filings, published surveys and vendor price lists — and links to the document it comes from. Data is re-checked against its sources when the site is updated, and the date of the last update appears on every page. No firm or vendor pays to be listed, and nothing is ranked.
Status labels
| Label | Meaning |
|---|---|
| Filed | Computed from fees disclosed in SEC or court filings. The filing is linked on every row. |
| List price | From the vendor's own published price list, with the date it was checked. |
| Survey | Quoted from a published survey, market report or a firm's own published price. The year is shown; older studies are flagged. |
| Formula | A published fee formula (Lehman, Double Lehman) applied to the inputs. A reference point, not an observed fee. |
Sources
| Dataset | Source | Records | Period |
|---|---|---|---|
| M&A advisor and fairness-opinion fees | SEC EDGAR DEFM14A merger proxies and SC 14D9 tender-offer statements | 626 filings · 782 advisor records | 2023-01 to 2026-09 |
| IPO spreads and offering expenses | SEC EDGAR 424B4 final prospectuses and the last S-1/F-1 before pricing | 491 IPOs · 245 itemized | 2023-01 to 2026-09 |
| Placement agent fees | SEC Form D quarterly data sets | 49,040 raises | 2023 Q1 to 2026 Q2 |
| Chapter 11 retention terms | US Bankruptcy Court dockets via CourtListener RECAP | 46 cases · 95 professionals | Petitions 2023–2026 |
| Diligence, insurance, escrow and private-deal benchmarks | Published surveys, broker reports and firm price lists | 132 data points | Mostly 2024–2026; older studies dated |
| Data room pricing and vendor facts | Vendor pricing pages; third-party pricing research for quote-only vendors | 25 vendors | Checked 2026-08-27 and 2026-09-13 |
| Advisor tiers | Wikipedia, Mergers & Inquisitions, LSEG, Axial, Am Law, PCAOB, INSIDE Public Accounting | 27 lists · 639 listings | 2023–2026 editions |
Sample sizes and what each one counts
The M&A figures use several different counts. Each statistic on the site states which one it uses; they are not interchangeable.
| Count | Number | Definition |
|---|---|---|
| Filings reviewed | 626 | DEFM14A merger proxies and SC 14D9 tender-offer statements filed 2023-01-01 to 2026-09-13 whose fee sections were read. |
| Filings with an advisor record | 562 | Filings with at least one financial-advisor record in the download. |
| Filings with a stated fee | 549 | Filings where at least one advisor record states a total fee or an opinion fee. |
| Advisor records | 782 | One row per advisor per filing in ma_advisor_fees.csv. |
| Records with a total fee | 716 | Advisor records stating the advisor’s total fee. |
| Records with an opinion fee | 513 | Advisor records stating the portion payable on delivery of the fairness opinion. |
| Deals with a usable value | 380 | Filings with a stated or computed deal value, excluding SPAC mergers and values flagged for review. Fee-as-%-of-value statistics use these. |
| Statements excluded | 57 | Extracted fee statements that failed quote verification. |
Verification
- Every quoted fee is checked against the filing. An advisor fee is included only if the sentence quoted for it appears word for word in the filing text and the fee amount appears in that sentence. 57 statements failed this check and are excluded.
- Deal values are stated or computed, never inferred. A stated value must appear in its quoted sentence. Otherwise value is the cash price per share in the filing × shares outstanding (the record-date count in the same filing, or the latest XBRL cover figure). Deals where the two disagree by more than 2× are excluded from percentages.
- Comparables widen only as needed. The calculator starts with deals within 2× of your size and widens to 3×, 5× and 10× until it has enough rows; the window used is printed on each line.
- Every vendor is priced by the same rule. Each data room appears at its lowest listed tier that fits your inputs.
Known gaps
- Public filings cover public-company targets and IPOs. Private M&A under $150M relies on advisor surveys.
- M&A legal fees are not disclosed deal by deal; the calculator uses published legal-spend surveys and hourly rates.
- Big Four quality-of-earnings fees are not published.
- No public source supports a "national or regional" split of audit firms beyond the PCAOB and IPA lists.
- Firm names follow the filings; mergers since filing (for example Cowen into TD, Moss Adams into Baker Tilly) may not be reflected.
Licence and citation
The data is licensed CC BY 4.0. Cite the page used as Deal Cost Index, “<page title>”, updated September 14, 2026, with a link.
Versions and citation
The current data version is 2026.09.1. Each version is kept as a fixed set of files under data/export/releases/<version>/; the files in data/export/ always hold the latest version. When figures change after publication, the version number changes and the earlier files stay available.
Cite a page as Deal Cost Index, “<page title>”, data version 2026.09.1, with a link to the page. Cite a file as Deal Cost Index, <file name>, data version 2026.09.1, CC BY 4.0. The licence covers the compiled data; quoted text and figures remain those of the filings, vendors and publications cited in each row.
| Version | Date | Changes |
|---|---|---|
| 2026.09.1 | 2026-09-14 | Data room pricing re-checked on each vendor’s own site; totals now show the months billed; plans, observations and budget examples published as separate files; third-party estimates kept only with a named source; M&A sample counts defined separately. |
Downloads
Every table on this site is built from these files. Each row keeps the link to the filing or publication it comes from. A manifest lists columns and row counts.
- M&A advisor fees — 782 advisor records with the quoted sentence and filing link
- IPO costs — 491 IPOs with spread, itemized expenses, auditor, counsel and underwriters
- Placement fees by segment and by broker-dealer — Form D, 2023Q1–2026Q2
- Chapter 11 retention terms — 95 professionals in 46 cases
- Survey benchmarks — 132 published data points
- Advisor tier lists — 639 listings from 27 public lists
- Data room vendor profiles — 25 vendors: self-description, disclosure state, stated certifications, ownership and official profiles
- Data room plans — 164 plans as listed by each vendor: price, currency, billing, billable unit, seat and storage limits, and source page
- Data room pricing observations — what each vendor’s site shows, when it was last read, and any sourced third-party estimate
- Data room budget examples — the fixed examples on the data room page, with plan chosen, months billed, units and totals