A corporate merger is approved in stages, and no single signature completes it. The buyers and the target sign a merger agreement first. Then the deal must clear antitrust review, win shareholder approval where required, and satisfy the closing conditions written into the contract. Any one of those steps can delay or kill the transaction.
This article walks through the sequence: who reviews the deal, who votes on it, and what happens between signing and closing. The timeline matters because most large deals take months, not weeks, and the parties must stay independent competitors until the regulators finish.
What actually happens when two companies sign a merger agreement?
Signing is a contract, not a completed merger. The board of each company approves the deal terms, and the companies sign a merger agreement that sets the price, the structure and the conditions that must be met before the deal closes. A corporation, as Wikipedia's overview of the corporation explains, is a legal entity authorized by the state to act as a single legal person, with shares owned by shareholders who generally elect a board of directors to control the company. That structure is why board approval comes first: the directors, not the shareholders, negotiate and sign.
The agreement usually includes a termination fee, a list of closing conditions, and promises about how each company will run itself until the deal closes. Those interim promises matter to regulators, because the two companies are still separate competitors while the review is pending.
Why does antitrust review come before closing?
Antitrust review exists to stop deals that would reduce competition. In the United States, large mergers are reported to the federal government under the Hart-Scott-Rodino Act, which starts a waiting period before the deal can close. Our HSR merger review explainer covers the waiting periods, the second request process and the gun-jumping rules in detail. For related coverage, see HSR Merger Review Explained: Waiting Periods, Second Requests and Gun-Jumping.
The practical point is simple: the parties cannot close during the waiting period. If reviewers see a competition problem, they can extend the review, negotiate a settlement that requires divestitures, or sue to block the deal. Most deals clear without a challenge, but the review is a real gate, not paperwork.
Deals with a foreign buyer face an extra layer. A foreign investment in a US business can require national security clearance through CFIUS, the interagency committee that reviews foreign acquisitions; see our CFIUS review explainer for when that clearance is needed and what it involves.
When do shareholders get to vote on a merger?
Shareholder approval is required in most public-company mergers, because the target's shareholders are giving up their stock. Under Delaware corporate law, which governs most large US public companies, the board recommends the deal and the shareholders vote at a meeting called for that purpose. The proxy statement sent before the vote discloses the terms, the board's reasons and the financial analysis behind the price.
The vote is not always a formality. When the buyer or its affiliates sit on both sides of the deal, the transaction is conflicted, and the process adds protections for minority holders. Our coverage of special committees in conflicted deals explains how an independent committee and a majority-of-the-minority condition are used to give the vote real weight.
Going-private transactions add another layer of minority protection under federal securities rules, covered in our Rule 13e-3 explainer. This connects to our earlier piece, Going Private Under Rule 13e-3: Special Committees and Minority Protection.
What other approvals can a merger need?
Antitrust and shareholder votes are the headline gates, but they are not the only ones. Depending on the industries involved, a deal may need:
- Approval from sector regulators, such as banking or communications authorities, before the business can be combined.
- Clearance from foreign competition authorities when the combined company sells in their markets.
- Consents from lenders, landlords and key customers whose contracts require notice or approval on a change of control.
- Court or third-party approvals in rare cases where litigation or contract terms require them.
Each of these is a closing condition. If one is not met by the deadline in the agreement, either party may be able to walk away, sometimes by paying or collecting a termination fee.
How long does the approval timeline take?
The honest answer is that it depends on the deal's size and overlap. A merger with no antitrust issues and an uncontested shareholder vote can move from signing to closing in a few months. A deal that draws an extended antitrust review, a second request, or a regulatory challenge can take much longer, and some deals are abandoned after a year or more of review.
Three events drive the clock:
- The antitrust waiting period, which starts when the parties file and ends when the reviewers let it expire or clear the deal.
- The proxy process and shareholder vote, which requires preparing, mailing and soliciting proxies before the meeting.
- The satisfaction of remaining closing conditions, including regulatory consents outside the United States.
Because the parties must operate as independent companies during this window, they are restricted in what information they can share and what competitive decisions they can coordinate. Those limits are the gun-jumping rules referenced above.
What this means for anyone following a deal
Our analysis: treat a signed merger agreement as a proposal, not a done deal. The reliable signals of progress are procedural. A waiting period that expires on schedule, a shareholder vote that passes, and the absence of a regulatory challenge are the markers that a deal is moving toward closing. A second request, a lawsuit from a competition authority, or a shareholder vote that fails are the markers of trouble.
The trade-off for deal parties is baked into the structure: the same review steps that protect competition and minority shareholders also add months of uncertainty, and uncertainty is where deals die. For readers tracking a specific transaction, the filings themselves — the merger agreement, the proxy statement and the regulatory notices — are the best running record of where the approval stands.
Corporate mergers sit inside a broader body of law and regulation. For more coverage in this area, see our law section and the rest of our corporate news coverage.
