Recently, I started researching why so many startups and tech companies talk about stock options as if they were the best thing in the world for retaining talent. It turns out it makes perfect sense. Let me explain what they really are and why this financial instrument remains so relevant, especially in the tech ecosystem.

Let's break it down. Stock options originated in Silicon Valley back in the 1990s as an ingenious compensation formula. Instead of paying employees entirely in cash, companies offered them rights to buy shares of the company at a fixed price. Basically, you gave the worker the chance that if the company grew, they would benefit too. Clever, right?

So, what exactly is a stock option? It’s a right, not an obligation, that you have as an employee to purchase shares of your company at a predetermined price, known as the strike. That price is set at the time of the contract and remains the same throughout the option’s validity period. The interesting part is that you decide whether to exercise that right or not. If the company grows and the stock is worth more than your strike, you make money. If not, you simply don’t exercise and that’s it.

The functioning of stock options has several key components. First is the volume, which is the maximum number of shares you can buy under this agreement. Then the strike, that fixed price I mentioned. Next is the term, because these prices can’t stay fixed indefinitely as the company grows. And finally, something that distinguishes stock options from other derivatives: you don’t pay a premium. It’s offered as part of your compensation package.

Let’s look at a concrete example. Imagine you start working at a promising startup. Your compensation package includes stock options with these terms: a thousand shares, a strike of three euros per share, a maximum term of five years. Three years later, the company goes public and the shares are trading at six euros. You decide to exercise your options, pay three thousand euros, and acquire a thousand shares worth six thousand on the market. Implicit profit: three thousand euros. Your colleague, hired under the same conditions, decides to wait. A crisis hits, the price drops to two euros ten cents, and they choose not to exercise to avoid losses. That’s the power and risk of stock options.

Now, it’s important to distinguish between stock options and other financial derivatives, particularly futures. Both are derivatives whose value depends on an underlying asset. Both set a price today to be executed in the future. But here’s the crucial difference: futures are an obligation. You commit to buying or selling no matter what. Stock options are a right. You decide. Also, there are Call options, which allow you to buy, and Put options, which allow you to sell. All stock options are Calls because their goal is to give you a favorable purchase price.

Tech companies pioneered this because they have a different business model. A software startup can scale exponentially in just a few years. They don’t need to open physical stores in every country like Inditex or Walmart. That’s why it makes sense for them to incentivize their employees with shares. If the company explodes, everyone wins. If not, well, at least they tried together. In Spain, the Startup Law has even legitimized these practices as a hiring mechanism.

When you exercise a stock option, you enter one of three financial scenarios. In The Money means your strike is below the current stock price, so you have an implicit gain. At The Money is when they match exactly, which is statistically rare. Out of The Money is when the strike is above the current price, so it’s not worth exercising. In this last case, you simply let the option expire.

The benefits of stock options are quite clear. First, you get a tool with unlimited profit potential, not capped. Second, the company manages to genuinely retain employees, not mercenaries. Third, for you as a worker, it’s a purchase option without paying a premium, something you don’t get in the open market. Fourth, the company doesn’t spend immediate liquidity, allowing it to offer competitive compensation without breaking cash flow.

But risks do exist. Stock options guarantee nothing. If the stock never rises, you never profit. The gains you make are subject to taxes, so the final result is always less than expected. And some employees feel trapped, forced to stay longer at the company to avoid losing the advantage of these options.

From a tax perspective in Spain, stock options are taxed the same as ordinary shares. Your initial value is the strike, your final value is the sale price. The difference is your capital gain. With the current brackets, if your gain is five thousand euros, you pay nineteen percent, that is nine hundred fifty euros, leaving you a net profit of four thousand fifty. The brackets are applied progressively and in steps, not jointly.

Now, here’s the million-dollar question: can I invest in stock options as a regular investor? No. They are exclusively for employees contractually linked to the company. But there is something similar and accessible: stock options on the market. They work exactly like stock options, with the difference that anyone can buy them. The trade-off is that you have to pay a premium, which you don’t pay with stock options because they are part of compensation.

Stock options come in two flavors. Call options allow you to buy an asset at a predetermined price within a timeframe. You use this when you believe the asset will rise. Put options allow you to sell an asset at a predetermined price. You use these when you think it will fall. For example, if you buy a call on a stock at twenty dollars and it reaches thirty-five, you exercise and earn fifteen dollars per share. If you buy a put at forty dollars and the stock drops to fifteen, you exercise and sell at forty what’s worth fifteen, earning twenty-five dollars.

The reality is that stock options remain an effective talent retention mechanism, especially in the tech sector. They align interests: the employee wants the company to grow because their compensation depends on it. The company wants to grow because its employees are motivated. It’s a virtuous circle. Of course, it requires that the company truly has growth potential. Otherwise, stock options become an empty promise. But when they work, they work well. And that’s why they continue to be so popular decades after their invention in Silicon Valley.