Buy-side vs sell-side data rooms: who pays, who controls

Most people who say “the data room” mean the seller’s. That is the room bidders log into, the one with the Q&A queue, the watermarks and the activity reports. But on a serious acquisition there is often a second room nobody outside the buyer ever sees.

A sell-side data room is a secure online workspace where a company being sold, or its adviser, discloses documents to prospective buyers under controlled conditions. A buy-side data room is a workspace the acquirer runs for itself, to collect what it learns, the reports its advisers write and the plans it makes for the first hundred days after closing.

Same software category. Opposite jobs.

Who pays and who controls each kind of room?

The simplest rule holds almost everywhere: the party that opens the room signs the contract, pays the invoice and sets the permissions. Everything else follows from that.

The control point matters more than the cost. A seller will happily let a buyer read a contract; it will not let the buyer see who else is reading it. That is why bidders never get administrator rights in a sell-side room, however large they are.

Why would a buyer open its own room at all?

If the seller already built a beautiful room, a second one can look like duplication. It is not, for three reasons.

The seller’s room is not yours. You cannot add your own files, you cannot comment, and when the process ends the seller switches off your access. Anything you did not save locally is gone.

Your advisers need somewhere to work together. Lawyers, accountants, tax specialists, environmental consultants and insurance brokers each produce reports. On a mid-market deal that can mean eight or ten advisory firms. Email chains and shared drives across that many firms are where version confusion starts.

Integration starts before signing. The people planning day one, from finance systems to HR, need diligence findings early. A buy-side room lets you open findings to them without exposing your bid strategy or your valuation model.

Serial acquirers, private equity funds and corporate development teams that close several deals a year tend to run a buy-side room on every deal as a habit. A first-time buyer making one acquisition often does not, and regrets it around week six.

Which way does information flow in each room?

The cleanest way to see the difference is to follow the documents. In a sell-side room they flow outward, from one seller to several bidders who are walled off from each other. In a buy-side room they flow inward, from many advisers to one team that has to make a decision.

Timing differs too. The seller’s room exists for the sale and is archived at closing. The buyer’s room usually opens once the buyer gets serious, around first-round bids, and outlives the deal because integration needs it. From first-round bids to signing, both are live at once, and that overlap is when documents most often cross from one room to the other without anyone checking whether that is allowed.

What can you copy from the seller’s room into yours?

Less than people assume. A typical confidentiality agreement allows the buyer to share evaluation material with its own representatives for the purpose of assessing the deal. It often says nothing explicit about uploading it to a separate system, and some sellers’ process letters forbid downloads entirely for sensitive folders.

In practice, buy-side rooms hold mostly derived work: your advisers’ reports, your issue lists, your models and your notes, with citations to the seller’s index numbers rather than copies of the seller’s files. That keeps you safe if the deal collapses and you must certify destruction of the seller’s material.

What does reverse due diligence look like?

When the consideration includes the buyer’s shares, an earn-out tied to the combined business, or a long-term commercial relationship, the seller has a real interest in the buyer’s health. So the seller asks questions.

This is reverse due diligence, and it flips the roles. The buyer now opens a small, outward-facing room to show the seller its accounts, cap table, material contracts and any litigation. It is a sell-side room in miniature, run by the buyer.

It is usually narrower than the main diligence. A seller receiving 30% of the price in buyer stock typically wants:

• the last two or three years of audited accounts and the current management accounts,
• the cap table and any instruments that could dilute the shares it receives,
• material debt facilities and covenants,
• significant litigation and regulatory matters,
• for an earn-out, the budget and reporting the earn-out will be measured against.

A few dozen documents, not thousands. But they need the same discipline as any outward room: watermarks, view-only access for the most sensitive items, and an audit trail you can rely on if there is a later dispute about what was disclosed.

How should a buy-side room be organised?

A sell-side index follows the target’s business: corporate, finance, tax, people, IP. A buy-side room follows the buyer’s workstreams instead, because its users are organised by what they are checking, not by what the target owns.

Folder 6 is the one that justifies the whole exercise. Your valuation, your walk-away price and your financing terms are the most sensitive documents in the deal, and they belong behind the tightest permission group you have.

How do permissions differ between the two sides?

In a sell-side room, permissions are about separation. Bidder A must never see that Bidder B exists, and each group gets exactly the folders its stage of the process allows.

In a buy-side room, permissions are about need to know. Everyone is on the same team, but not everyone should see everything:

• Outside advisers see their own workstream and the deal management folder.
• The investment committee sees summaries and approval papers.
• The integration team sees findings only once the deal is far enough along that a leak to staff would not damage it.
• Valuation material stays with three or four people.

Both sides benefit from the same core features: granular folder permissions, an audit trail and two-factor login. The difference is emphasis. Sell-side rooms lean hardest on watermarking, Q&A and bidder analytics; buy-side rooms lean on version control, commenting and fast onboarding of advisers who join mid-process.

Which features matter more on each side?

Not every feature carries the same weight. This is how we would weigh them when choosing a room for each role.

That last row matters to corporate buyers. If your IT team wants every system behind the company’s identity provider, check single sign-on early, because it is not universal. In our data, iDeals, Datasite, Intralinks and Ansarada list it; several otherwise strong rooms, Ellty and Firmex among them, do not. Our M&A use case ranks providers for both sides of a deal.

Who pays when the adviser opens the room?

On the sell side, investment banks and boutique advisers often open the room under their own account and pass the cost to the client, either as a disbursement or inside the success fee. The engagement letter should say which. If it is silent, ask before the room opens, because a long process with heavy storage can produce a meaningful bill.

Two things to agree in writing:

1. Who owns the room contract. If the adviser owns it and the relationship ends, you want the archive regardless.
2. Who receives the archive at the end. The seller needs a complete copy to defend the disclosure if a warranty claim arrives.

On the buy side, funds sometimes hold one long-running subscription and open a fresh room per deal. That favours providers with flat monthly pricing over per-page or per-project quotes. Most leading providers quote on request; a few publish a starting price. Ellty, for example, lists $149 per month and Box $15 per user per month. Treat those as indicative and confirm current terms with the provider. Our pricing page lists published starting prices for all 18 rooms we score.

What changes on a carve-out or a merger of equals?

Carve-outs. When a group sells one division, the seller’s room has to separate the division’s documents from the parent’s. Shared contracts, shared IT and shared employees create grey areas. The buyer’s room, meanwhile, carries extra workload on transitional services: what the parent will keep providing after closing, and for how long. Expect the buy-side integration folder to be the busiest.

Mergers of equals. Both parties diligence each other, so both open outward-facing rooms at roughly the same time. Each side’s room is sell-side from its owner’s point of view. Keep the two clearly named and keep separate administrator teams; mixing them up is how a document meant for one side ends up in the other’s room.

Competing buyers who are competitors. If a bidder competes with the target, the seller will often restrict the most commercially sensitive material to a clean team. That is a sell-side decision, but the buyer must mirror it: clean-team output should land in a restricted folder of the buy-side room, not in the general deal folders.

A short checklist for each side

If you are selling:

• Agree who owns the room contract and the final archive.
• Set one permission group per bidder, never per individual.
• Switch on watermarks and two-factor login before invitations go out.
• Decide whether Q&A answers are shared across bidders.

If you are buying:

• Read the NDA clauses on representatives, copies and destruction.
• Build the room around your workstreams, not the target’s folders.
• Put valuation and approval papers in a group of three or four people.
• Plan when integration staff get access, and keep the room past closing.