Employee equity comes in several forms, and the acronyms get used loosely enough that they are often confused. ESOP, ESPP, and RSU are three distinct instruments for giving employees a stake in the company, and they work in genuinely different ways — with different mechanics, different risk profiles, and different tax treatment. For founders deciding what to offer, and for employees evaluating an offer, understanding the differences is important. This guide lays them out.
ESOP — Employee Stock Option Plan
An ESOP gives employees stock options — the right to buy a certain number of the company's shares at a fixed price (the exercise or strike price) at some point in the future, after the options vest.
The defining feature of an option is that it is a right to buy, not a grant of shares outright. The employee has to actively exercise the option — pay the exercise price — to convert it into actual shares. The value to the employee comes from the difference between what the shares are worth and the (typically lower) exercise price they locked in. If the company does well and the share value rises above the exercise price, the options are valuable. If the share value falls below the exercise price, the options are "underwater" and worth nothing — the employee simply would not exercise them.
This is the most common form of equity in startups, particularly because it aligns employees with growth: options only pay off if the company's value increases. The employee takes on the risk that the options could end up worthless, which is the trade-off for the upside.
ESPP — Employee Stock Purchase Plan
An ESPP is a programme that lets employees buy company shares, usually at a discount, typically through payroll deductions over a defined period.
The mechanics are different from options. Rather than being granted a right to buy at a fixed strike price set at grant, employees in an ESPP elect to set aside a portion of their salary, which is then used to purchase company shares at a discount to the market price at defined purchase dates. ESPPs are most associated with publicly-listed companies, where there is a market price and liquidity, because the discount and the ability to potentially sell make them attractive.
The key distinction: an ESPP is the employee choosing to buy shares (at a discount) with their own money via payroll, whereas an option is the company granting a right to buy. ESPPs are a way for employees to accumulate equity steadily, and the discount provides immediate value, but the employee is putting in their own cash to participate.
RSU — Restricted Stock Unit
An RSU is a promise to give an employee actual shares (or their cash equivalent) at a future date, once vesting conditions are met — without the employee having to pay an exercise price.
This is the crucial difference from options. With an option, the employee must pay to exercise, and the value depends on the share price exceeding the strike. With an RSU, the employee pays nothing — once the RSU vests, they simply receive the shares. This means an RSU always has value as long as the shares have any value at all; there is no "underwater" scenario the way there is with options. An RSU vesting when the share is worth ₹100 gives the employee ₹100 of value per unit, regardless of any strike price, because there is no strike price.
RSUs are common at larger, later-stage, and public companies, where the certainty of value (no underwater risk) is attractive and the company can afford the more direct cost. They are simpler for employees to understand — you vest, you get shares — but they represent a more direct transfer of value from the company than options do.
The core differences at a glance
The three instruments differ along a few key dimensions.
With an ESOP (options), the employee gets a right to buy at a fixed price, must pay to exercise, takes on the risk that options could be underwater, and the upside is tied to the share price rising above the strike.
With an ESPP, the employee chooses to buy shares at a discount using their own money through payroll, typically at a listed company with a market price.
With an RSU, the employee is promised actual shares for free on vesting, pays nothing, and the units always have value as long as the shares do — no underwater risk.
In terms of risk and reward, options offer the most leverage (worthless if the company stalls, valuable if it soars), RSUs offer the most certainty (value as long as the company is worth something), and ESPPs offer a steady, discounted accumulation funded by the employee.
Tax treatment differs too
Each instrument is taxed differently, and the tax treatment is jurisdiction-specific. In broad terms, the taxable events and the basis for taxation differ between options, ESPPs, and RSUs — options are typically taxed around exercise and sale, RSUs around vesting and sale, and ESPPs around purchase and sale, with the specifics varying by country. For the India-specific treatment of options, see our detailed ESOP taxation guide. The important point is that the choice of instrument has tax consequences for employees, so the tax angle should be considered alongside the mechanics, and employees should confirm the current treatment for their instrument and jurisdiction with a qualified advisor.
When each is used
In practice, the instruments map roughly to company stage. Early-stage startups predominantly use stock options (ESOPs), because options align employees with growth and the company often cannot afford the direct cost of RSUs. As companies mature and especially once they are listed or near it, RSUs become more common, valued for their certainty. ESPPs are largely a feature of public companies, offering all employees a way to buy discounted stock. Many later-stage companies use a mix.
Common points of confusion
The recurring misunderstandings include:
Thinking options and RSUs are the same thing — they are fundamentally different, since options require paying a strike and can be underwater, while RSUs are free on vesting and cannot be underwater.
Assuming an ESPP is the same as being granted equity, when it is actually the employee buying shares with their own money at a discount.
Overlooking that options can end up worthless if the share price stays below the strike.
Not appreciating that the tax treatment differs significantly across the three.
Comparing offers from different companies without accounting for whether the equity is options, RSUs, or something else, which makes a straight numerical comparison misleading.
Why the instrument and your systems should connect
Whichever instrument a company uses, it has to be administered — grants tracked, vesting calculated, exercises or purchases processed, and the tax handled through payroll. When equity administration lives in a spreadsheet disconnected from the cap table and payroll, keeping the records accurate and handling the taxable events correctly becomes a manual burden, regardless of which instrument is in play.
When equity management, the cap table, and payroll sit on a single database, the instrument's lifecycle is handled coherently — grants and vesting tracked, the taxable event (exercise, vesting, or purchase) flowing through to payroll and the cap table together. This is how Helion is built, with ESOP and equity living alongside payroll on the same schema, so that whatever form the equity takes, the administration and the tax stay consistent and the records stay current. For a company offering employee equity, that connected design removes the administrative drag that otherwise grows with every grant.
This guide gives general information comparing employee equity instruments and is not legal, tax, or financial advice. The mechanics and especially the tax treatment of ESOPs, ESPPs, and RSUs vary by jurisdiction and by each company's plan, and should be reviewed with qualified advisors in the context of your specific situation.