securetools.live • November 2026Electronic Signatures in Due Diligence: NDAs, LOIs, and M&A Documents
Electronic signatures are accepted for NDAs, LOIs, and most M&A definitive agreements in the US and EU. The critical workflow is: NDA signed first, data room access granted after. For sensitive document sharing alongside NDA workflows, tracking who opens shared materials after signing is as important as the signing record itself.
The Role of E-Signatures in Due Diligence
Due diligence in M&A, fundraising, and commercial real estate transactions is a multi-stage process involving a predictable sequence of signed documents: confidentiality agreements before information is shared, letters of intent or term sheets once initial agreement is reached, and definitive agreements at closing. Electronic signatures accelerate each stage and create an unambiguous record of when each party committed.
For M&A specifically, the ESIGN Act in the United States and eIDAS in the EU both establish that electronic signatures have the same legal effect as ink signatures for commercial transactions, with limited exceptions for specific document types. The foundational legal framework is covered in the guide on whether electronic signatures are legally binding.
For deal teams, the practical benefit is speed: a counterparty can sign a mutual NDA within minutes of receiving it, rather than the 24–48 hours typical of ink-signature workflows. For competitive processes with tight timelines, this difference can affect whether a party makes the information deadline.
NDA Before Data Room Access
The most consequential timing issue in due diligence is ensuring that the NDA is fully executed before any confidential information is shared. The signed NDA and the audit trail's timestamp create the chronological record that protects the disclosing party if information is later misused.
The workflow should be:
- Send the NDA for signature via your e-signing platform.
- Both parties sign. Confirm the envelope is fully completed — not just signed by one party.
- Download and store the executed NDA and its audit trail.
- Grant data room access. The timestamp on the access grant should be after the NDA completion timestamp.
For NDA-specific workflows and templates, see the guide on how to create, send, and sign an NDA online.
LOI and Term Sheet Signing
Letters of intent and term sheets vary in their legal effect — some are explicitly non-binding (with the exception of specific binding provisions such as exclusivity and confidentiality), while others are intended to create binding preliminary obligations.
For non-binding LOIs, an e-signature via a standard platform (email-link authentication) is appropriate — the stakes at signing are primarily around evidencing good faith and the agreed commercial terms, not creating enforceable obligations. For LOIs that include binding provisions — exclusivity periods, break fees, confidentiality — the same signing standard as a definitive agreement is appropriate.
In either case, the audit trail timestamp is useful: it establishes when the parties agreed to the terms, which matters if one party later claims the LOI doesn't reflect the agreed terms or was signed under duress.
Definitive Agreements: APA, SPA, and Merger Documents
Asset purchase agreements (APA), stock purchase agreements (SPA), and merger agreements represent the most significant documents in a transaction. The signing mechanics for these documents are often negotiated between counsel on both sides.
In the US, electronic signatures are accepted for these agreements under the ESIGN Act for most commercial transactions. Large transactions with institutional counterparties increasingly sign definitively agreements electronically — it is no longer uncommon even for nine-figure transactions.
For multi-party signing — where both buyer and seller, plus potentially guarantors or consent parties, must execute — the sequential routing workflow is appropriate. Each party's counsel typically requires that their client signs on specific signature pages rather than across the entire document, which is easily configured as per-recipient field placement in a signing platform.
For the mechanics of collecting multiple signatures, see how to collect multiple signatures on a document electronically.
Secure Document Sharing After Signing
After the NDA is signed, the due diligence phase begins in earnest. The disclosing party needs to share potentially sensitive financial, operational, and legal materials with the counterparty. How those documents are shared — and tracked — is as important as the signing record.
Virtual data rooms (VDRs) are the standard tool for large-transaction due diligence — they provide access-controlled repositories with per-user permissions and activity logs. For smaller transactions or early-stage information sharing (sharing a pitch deck or executive summary before the formal data room opens), a secure document-sharing tool with access tracking provides a lighter alternative.
Teams that need to share documents with counterparties after NDA signing — for example, distributing a pitch deck or financial summary before a formal data room is opened — can use SendNow to share files securely and track who opened each document and when, complementing the NDA's signing record with a view-level activity log.
Record-Keeping Requirements for M&A Transactions
Executed transaction documents and their audit trails must be retained for extended periods. The indemnification periods in most M&A transactions (typically 12–24 months post-closing for general reps and warranties) establish the minimum practical retention window. The full limitation period for claims — typically 3–6 years for contract claims in the US, up to 12 years for deeds in England and Wales — establishes the outer bound.
- Store the executed definitive agreement PDF together with the signing platform's Certificate of Completion/audit trail as a single archive.
- Retain the NDA separately — it may be the document under which a breach claim is made years after closing.
- Include all ancillary documents (schedules, disclosure letter, closing deliverables) in the archive — not just the main agreement.
- For QES documents (used in EU cross-border transactions), ensure long-term validation (LTV) is embedded in the PDF to maintain verifiability after certificate expiry.
For a detailed discussion of audit trail retention and what they contain, see electronic signature audit trails.
Frequently Asked Questions
In most US jurisdictions, asset purchase agreements, stock purchase agreements, and merger agreements can be signed electronically under the ESIGN Act. In the EU, they are accepted under eIDAS for most commercial transactions, though some Member States require notarization for real property transfers within an acquisition. In practice, large-transaction counsel on both sides often negotiate the signing mechanics — sometimes requiring counterpart ink signatures or notarized copies for specific schedules. The underlying asset purchase itself may trigger real estate transfer requirements that override the base ESIGN framework for those specific documents.
About the Author: Mohamed Siraj
Mohamed Siraj is a security researcher and technical writer focused on document security, file-sharing workflows, and compliance tooling for distributed teams.