What is a takeover bid (OPA, Public Tender Offer)?

In the financial world, few operations attract as much attention as an OPA. Behind these initials —which stand for Public Takeover Bid— lies a mechanism that, although technical in appearance, can trigger real shocks in the stock market. An OPA is, essentially, an offer made by a company, a fund, or even an individual to acquire shares of another company, usually publicly listed. It is one of the most important operations in the financial sphere and, therefore, requires the supervision of professionals with extensive experience and high-level training, such as that provided by a Global MBA or a Master in International Business STEM. Launching an OPA can serve to expand business into new sectors or geographies, strengthen a company’s position in a competitive market, achieve cost-reducing synergies, or even access strategic technologies.

How does an OPA work?

Every OPA begins with a decision: that of the potential buyer, also called the bidder, who decides to acquire a significant stake in a listed company. To do so, they launch a formal offer specifying the number of shares they wish to purchase, the price they are willing to pay usually including a premium over the current market value, the conditions of the deal, and the deadlines. This offer must be communicated to and approved by the CNMV (Spanish National Securities Market Commission), which acts as the guarantor of the process.
Once the offer is published, the target company the listed firm must issue a public assessment recommending whether shareholders should accept or reject it. It may support the deal (friendly takeover) or oppose it (hostile takeover), which can sometimes lead to high-stakes corporate battles. In fact, defensive mechanisms may be activated, such as seeking a “white knight” (another buyer offering a competing bid), increasing share value, or selling strategic assets to discourage the bidder.
It is important to know that once launched, an OPA is irrevocable: the bidder cannot withdraw, unless the specific conditions they set are not met. For example, if they establish that the deal is only valid if at least 65% of the capital accepts the offer and this threshold is not reached, the OPA is considered unsuccessful. Conversely, if the percentage is achieved, the bidder gains effective control of the company.
The process follows a series of regulated steps:

1. Notification and prospectus: the bidder informs the CNMV and publishes a detailed document about the offer.
2. Analysis of the target company: the involved company issues its response and evaluates whether to accept or reject.
3. Acceptance period: a timeframe is opened (usually between 15 and 30 business days) for shareholders to decide.
4. Outcome: if conditions are met, the purchase is executed and ownership changes hands.
    

Types of OPA according to the CNMV

Although it may seem like a single concept, there are actually different types of OPAs, classified under CNMV regulations. This variety responds to the different situations that may arise in the markets. We have already discussed the difference between a friendly and a hostile takeover, but there are other types.

A voluntary OPA is one launched by the buyer’s own decision. It is not legally required, but rather a strategic business move. It can target 100% of the capital (total) or just part of it (partial). In this case, the bidder sets the price and the number of shares they wish to acquire.
In contrast, there is also the mandatory OPA, imposed by law. This occurs when a shareholder exceeds 30% of the voting capital of a listed company. In such cases, they must launch an offer to acquire the remaining shares, ensuring minority shareholders can exit if they do not agree with the new balance of power.

Another case is the residual OPA, which occurs when a shareholder reaches or exceeds 90% of the capital. At this point, the law requires them to buy the remaining shares if minority shareholders request it, or the company may even be forced to delist from the stock exchange, a process known as delisting.
They can also be classified according to the form of payment:

• In a standard OPA, shareholders receive cash in exchange for their shares.
• In an exchange offer (OPI), instead of cash, shares of the bidder company are delivered.

• In an mixed OPA (OPAC), the compensation is combined: part cash and part shares.
    

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What is a stock market and how does an OPA affect it?

As those studying a Master in Finance or a Master in Financial Management know, the stock market is the ecosystem where companies, investors, funds and public institutions buy and sell securities such as shares, bonds, or other financial products. When a company is listed, anyone can invest in it by acquiring a portion of its capital. This mechanism ensures market liquidity and provides companies with a way to finance themselves.
However, OPAs disrupt this balance. From the moment an offer is announced, the target company’s shares usually rise sharply, as investors anticipate receiving a price higher than the market value. This premium acts as an incentive to sell.
But the impact goes beyond price. An OPA can completely change the structure of a sector, eliminate a competitor, increase concentration, or even affect employees, suppliers, and clients. If it results in a merger or delisting, investors have fewer options and the competitive landscape changes.
In addition, a hostile OPA can generate weeks of instability, speculation, and defensive or opportunistic movements by institutional shareholders. Public perception also matters: an offer seen as aggressive or unfair may face criticism or regulatory resistance.
 

Notable examples of takeover bids in the financial sector

One of the most recent and controversial examples in Spain’s financial sector is the takeover bid launched by BBVA for Banco Sabadell in May 2024. The goal was to create a banking giant with more than €1 trillion in assets and a dominant share in SME and retail banking. However, Sabadell’s board publicly rejected the proposal, considering it insufficient and unbalanced. The operation was classified as hostile, as BBVA proceeded without the support of the Catalan bank’s management.
Despite this, the CNMC approved the deal in April 2025, although it imposed conditions: maintaining branches, protecting SME clients, and ensuring employment guarantees. At the time of writing, the OPA is still awaiting government approval, making this one of the most complex and discussed cases in recent years.
Other notable examples:

• Microsoft on Yahoo! (2008): a $44.6 billion offer rejected. Failed, but historic.
• Oracle on PeopleSoft (2003–2005): a two-year hostile takeover, completed for $10.3 billion.
• Anheuser-Busch InBev on SABMiller (2015–2016): one of the largest mergers in history (over $100 billion).