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. Data room vendors are always listed alphabetically; other tables are ordered by the figures 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.
To report an error, send a correction, or ask about the data, write to data@dealcostindex.com. Please include the page and the row or figure concerned, and a link to the source that disagrees with it. Confirmed errors are corrected in the next data version and noted in the version history below.
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 | 660 filings · 819 advisor records | 2023-01 to 2026-10 |
| IPO spreads and offering expenses | SEC EDGAR 424B4 final prospectuses and the last S-1/F-1 before pricing | 502 IPOs · 256 itemized | 2023-01 to 2026-10 |
| Placement agent fees | SEC Form D quarterly data sets | 52,571 raises | 2023 Q1 to 2026 Q3 |
| Chapter 11 retention terms | US Bankruptcy Court dockets via CourtListener RECAP | 47 cases · 96 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 | Every pricing page last read successfully between 2026-10-01 and 2026-10-29 |
| 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 | 660 | DEFM14A merger proxies and SC 14D9 tender-offer statements filed 2023-01-04 to 2026-10-28 whose fee sections were read. |
| Filings with an advisor record | 590 | Filings with at least one financial-advisor record in the download. |
| Filings with a stated fee | 577 | Filings where at least one advisor record states a total fee or an opinion fee. |
| Advisor records | 819 | One row per advisor per filing in ma_advisor_fees.csv. |
| Records with a total fee | 751 | Advisor records stating the advisor’s total fee. |
| Records with an opinion fee | 540 | Advisor records stating the portion payable on delivery of the fairness opinion. |
| Deals with a usable value | 381 | 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>”, data version 2026.10.3, with a link; versions are described below.
Versions and citation
The current data version is 2026.10.3. 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 2026.10.3, with a link to the page. Cite a file as Deal Cost Index, <file name>, data version 2026.10.3, 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 |
|---|---|---|
| 2026.10.3 | 2026-10-29 | Full refresh to October 29, 2026. Placement fees now include the SEC's 2026 Q3 Form D data set, the first quarter past 2026 Q2: 52,571 raises from 52,571. M&A: ten more merger filings read (660 from 650) and twelve more advisor records (819 from 807), including Patrick Industries and LCI Industries, Victory Capital's $7.03 billion purchase of First Eagle and Tempus's acquisition of Personalis. IPOs: 502 from 498, 256 with itemized expenses from 252. Annual audit fees: 9,498 rows from 9,420, fiscal 2025 now 2,157 companies from 2,084. Itemized merger expenses: 41 tables from 38. Data rooms: every vendor's pricing page was read again and no vendor changed a published price; Digify and Drooms were read in a browser, DocSend could not be read even in a browser and keeps the date it was last confirmed. The euro reference rate is 1.1133 US dollars (ECB, 2026-10-28), from 1.1298. 741 of the 839 vendor statements were found again and carry today's date; the rest keep theirs. 98 of 132 benchmark quotes and 12 of 27 tier lists were read again. Chapter 11 is unchanged at 47 cases: CourtListener's search API now requires an account token, so no new retention application could be read. |
| 2026.10.2 | 2026-10-14 | Ten more advisor-fee records from six merger proxies filed 2026-10-05 to 2026-10-14, plus four filings fetched in an earlier pass but never extracted. The EDGAR search windows now end on the day the search runs; they had been fixed at 2026-10-01, which hid filings made after that date. Data room prices were re-read on 2026-10-14 and none had changed. |
| 2026.10.1 | 2026-10-01 | Full refresh to October 1, 2026. Data rooms: FirmRoom raised its plans to US$395, US$795 and US$1,195 a month for 2, 5 and 10 GB (from US$395, US$695 and US$995) and now sells capacity as 1, 3 and 5 active rooms sharing the storage; DocSend’s pricing page was read in a browser again and shows Advanced Data Rooms at US$180 a month billed yearly or US$300 billed monthly, the same figures as before; Dillien’s €600 per room is unchanged and its page now states prepaid discounts of 10, 15, 20 and 30% for 4, 6, 8 and 12 months; no other list price changed. The euro rate is 1.1298 US dollars (ECB, 2026-10-01), from 1.1551. 797 of the 839 vendor statements were read again on the vendor’s own pages and carry today’s date; the other 42 keep the date they were last seen. Peony’s stated customers went from 6,800+ to 8,000+ teams. Dillien, Datasite, Ideals, Ansarada and FirmRoom changed their sites and their statements were replaced; statements that are no longer on a site were removed (Dillien: IPO, board, litigation, banks and technology; FirmRoom: biotech and real estate; Peony: technology), and vdr_features.csv gains two rows because Dillien now states two-factor authentication and EU data residency. M&A advisor fees: 14 merger filings dated September 14 to 29 added (626 to 640 filings, 782 to 797 advisor records); 18 older advisor records in 15 filings are now flagged because the advisor fees exceed 20% of the deal value, which means the deal value was misread, and they stay in the file but are left out of the fee-percentage statistics. IPO costs: 498 IPOs from 491, seven added (four priced September 21 to October 1 and three earlier ones the previous list had missed), 252 with itemized expenses from 245. Annual audit fees: fiscal 2025 added from 2026 proxies (2,084 companies) and fiscal 2024 now has 2,564 companies from 2,379. Law firm engagements: 1,259 from 1,247. Chapter 11: Pacifica of the Valley Corp. (Houlihan Lokey, US$100,000 a month) added, 47 cases and 96 professionals. Benchmarks and tier lists: 100 of 132 benchmark source quotes and 14 of 27 tier lists were read again on their sources. Placement fees still cover Form D filings through Q2 2026 because the SEC had not published the Q3 data set on October 1. |
| 2026.09.11 | 2026-09-29 | No prices changed. Dillien re-read after it published a new M&A page; it now names sell-side and buy-side M&A, and data_room_vendors.csv records both situations. |
| 2026.09.10 | 2026-09-23 | ma_transaction_expenses.csv: units printed with a table (“in thousands”) are now applied, which moves one table (Avangrid) to review because its printed items do not add up to its printed total; 38 tables remain. Adds the company’s counsel named in the same proxy. annual_audit_fees.csv gains fiscal 2023 and fiscal 2022, one row per company and year, with a flag where two proxies report the same year and agree. |
| 2026.09.9 | 2026-09-23 | No existing figures changed. Two new files: ma_transaction_expenses.csv, the estimated fees and expenses itemized in 39 merger proxies, kept only where the items add up to the stated total; and annual_audit_fees.csv, fiscal 2024 audit fees of US public companies from their 2025 proxy statements, with calendar-2024 revenue. |
| 2026.09.8 | 2026-09-23 | No existing figures changed. New file law_firm_engagements.csv: 1,247 appearances of 285 law firms across the IPO, M&A and Chapter 11 records, with the role, the company or case and an amount only where one is disclosed. |
| 2026.09.7 | 2026-09-22 | No fee amounts changed. The M&A advisor fee file gains the part of each fee payable only if the deal closes and that part’s share of the fee, kept only where the quoted sentence states it or states the total and the other part (486 of 782 advisor records). |
| 2026.09.6 | 2026-09-22 | No prices changed. Sector pages now cover all fourteen sectors in the fixed list: the budget examples file gains a public-sector room, and the vendor file’s sector entries were re-checked for construction on every vendor’s own site. |
| 2026.09.5 | 2026-09-22 | No prices changed. New file vdr_features.csv: which of 21 fixed features each vendor states on its own website, with the vendor’s words and the page, checked 2026-09-21. The budget examples file gains fifteen sector rooms (biotech, healthcare, real estate, mining, oil and gas, renewables, software, financial services, manufacturing, consumer, construction, education and law firms), each with its sector. |
| 2026.09.4 | 2026-09-16 | No prices changed. The budget examples file gains three more use-case rooms (a biotech or pharma licensing room, a single commercial property sale, a distressed or restructuring sale), bringing it to four budget examples and eight use-case rooms. The vendor file gains the situations each vendor’s own pages name, from one fixed list of thirteen applied to every vendor, with the date the pages were read. |
| 2026.09.3 | 2026-09-16 | No prices changed. The data room vendor file gains what each vendor states about who its product is for, which customers it names, and four buyer-fit facts (external viewers, monthly billing, sign-up, free plan or trial), each with the page it was read from on 2026-09-16; the budget examples file gains five use-case rooms alongside the four budget examples, with the use case’s id and the sentence describing it. |
| 2026.09.2 | 2026-09-15 | No figures changed. The data room vendor file’s description now gives the dates of the last successful pricing-page reads (2026-08-27 to 2026-09-15) instead of 2026-09-13/14; the budget examples file carries the new version number. |
| 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 — 819 advisor records with the quoted sentence and filing link
- IPO costs — 502 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 — 96 professionals in 47 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