One wrong recipient can hand your pricing to the bidder you're negotiating against.
A live deal means a dozen "John"s across three data rooms, all needing an update before the deadline. Autocomplete doesn't know which one you meant — it just picks the last one it saw.
It's not the analyst's fault. It's the number of parallel threads.
A live sell-side process might have three or four bidders running in parallel, each with their own advisor, their own John or Sarah on the deal team, and their own thread of near- identical subject lines — "Re: Project Falcon — Updated Model." An analyst working two bids at once forwards the updated cap table to the wrong "John," and now a competing bidder has your client's pricing floor, or worse, sees exactly what the other side is willing to pay.
That's not an email you can walk back with an apology. Once a competing bidder has seen pricing, they adjust their offer accordingly — and your client just lost negotiating leverage they can't get back. If the leak involved a party under an NDA, you're also now looking at a breach conversation with legal, not just an awkward one with your client.
And it isn't limited to pricing. Cap tables, management presentations, and diligence materials sent to the wrong domain can tip off employees, competitors, or the market before the deal is ready to be announced — turning a controlled process into a fire drill.
What the sender sees in Outlook — before the email leaves the outbox.
The data room controls access. It doesn't control your Outbox.
Most deal teams lean on a secure data room (Intralinks, Datasite, etc.) to gate who sees what — and it's genuinely effective for the documents that live inside it. The gap is everything that travels by email instead: the cover note, the summary deck, the redline sent for a quick turnaround because the data room workflow is too slow for an 11pm ask. None of that is covered once it leaves the platform.
The other standard answer is "slow down and double-check the To field." That's a fine instinct and a terrible control during a live process, where a single senior banker might be sending 80+ emails a day across multiple simultaneous deals. The people best positioned to catch the mistake are also the ones with the least time to look for it.
A guardrail on the Outbox, not just the data room.
Sendasta checks the recipient list — To, Cc, and Bcc — against rules you set, at the exact moment you click Send in Outlook. It never reads the body or attachments, so the deck, the model, and the cap table stay exactly as confidential as they were before the check ran.
- Blocked domains — flag a competing bidder's domain outright. If it appears as a recipient, the send is paused before anything goes out.
- No-combine pairs — flag two domains that should never appear on the same thread, like two competing bidders. Sendasta blocks the send if both show up, however they got there.
- Trusted pairs — mark legitimate multi-party combinations (co-advisors, lenders) as trusted once, so you're not interrupted on every send for a relationship you've already vetted.
For firm-wide protection across every active mandate, an admin pushes shared blocked-domain rules to the whole deal team via the Microsoft 365 Admin Center. Individual bankers can layer their own per-deal rules on top for the parties specific to their current mandate.
Frequently asked
Does Sendasta read the content of deal documents or attachments?
No. Sendasta only checks the addresses in the To, Cc, and Bcc fields against your firm's rules. It never opens the term sheet, the cap table, or the data room link itself — the check happens locally in Outlook the moment someone clicks Send. Nothing about the deal's substance is ever transmitted anywhere.
Can it stop a term sheet from reaching a competing bidder by accident?
Yes — flag the competing bidder's domain as blocked, and any email addressed to it gets paused before it sends, regardless of who typed it or how it ended up in the To field. You can also flag a "no-combine" pair if two bidders should never end up on the same thread together.
Will this slow down a live deal with dozens of emails a day?
No — the check adds under a second and only interrupts a send when it actually matches a rule you set. Every other email — the bulk of what goes out during a live deal — sends exactly as fast as it does today.
Can different deal teams have different rules?
Each team member's rules are their own — you're not stuck with one blanket policy across every live deal. For firm-wide guardrails (blocking known conflict-of-interest domains across all matters), an admin can push shared policy via the Microsoft 365 Admin Center on top of what individuals set.
Protect the deal before the send, not after.
Get started free for personal use, or reach out and we'll walk you through setting up firm-wide policy for your deal teams.