Employer Payroll Taxes on Stock Options: A Comprehensive Guide

Understand employer payroll taxes on stock options and strategies to manage tax implications. Maximize benefits with our comprehensive guide.

Written by PocketCfo Team

Reviewed by Terry Gu, CPA

4 minutes read

Stock options are a popular form of compensation among employers, especially in startups and tech companies. They not only offer employees a potentially lucrative benefit tied to the company’s success but also present various tax implications for both the employer and the employee. Understanding the nuances of employer payroll taxes on stock options is crucial for both parties to navigate the tax landscape effectively. This guide provides a thorough overview of the tax treatment of stock options, focusing on employer responsibilities and strategies to manage these obligations.

Also Read: Employer Payroll Tax Account Number vs. EIN

What is a Stock Option?

A stock option grants employees the right, but not the obligation, to buy a certain amount of company stock at a predetermined price, known as the exercise price, within a specific timeframe. It’s a way for companies to incentivize and retain top talent by aligning the employees’ interests with the company’s growth objectives.

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Types of Stock Options

There are two main types of stock options: Incentive Stock Options (ISOs) and Non-Qualified Stock Options (NSOs), each with distinct tax treatments and implications for both employees and employers.

Incentive Stock Options (ISOs)

ISOs are exclusive to employees and offer favorable tax treatment under the IRS code. When an employee exercises an ISO, they do not incur immediate ordinary income tax liability, and the employer does not have a corresponding tax deduction. However, the spread (the difference between the stock’s fair market value at the exercise and the exercise price) may be subject to the Alternative Minimum Tax (AMT) for the employee.

Non-Qualified Stock Options (NSOs)

NSOs can be granted to employees, directors, contractors, and others. Unlike ISOs, when NSOs are exercised, the spread is treated as ordinary income to the employee and is subject to employer payroll taxes. The employer can claim a tax deduction for the amount treated as income to the employee.

Also Read: The Employer Cost of Payroll Taxes: A Comprehensive Breakdown

Employer Payroll Taxes and Deductions

When an employee exercises NSOs, the employer is responsible for withholding income taxes and remitting payroll taxes, including Social Security and Medicare taxes. This event creates a taxable income equal to the difference between the exercise price and the fair market value of the stock at the time of exercise.

Tax Deductions for Employers

Employers can claim a tax deduction for the amount that is considered taxable income to the employee upon the exercise of an NSO. This deduction aligns with the timing of the employee’s income recognition, essentially when the option is exercised, not when it is granted.

Tax Reporting Requirements

For ISOs:

  • Form 3921: Employers must provide employees who exercise ISOs with Form 3921, detailing the exercise of an Incentive Stock Option under Section 422(b). This form helps employees report necessary information on their tax returns.

For NSOs:

  • Tax Withholding and Reporting: Employers must withhold applicable income and payroll taxes at the time of NSO exercise and report this compensation on the employee’s Form W-2.

Strategies for Managing Payroll Taxes on Stock Options

  1. Timely Tax Withholding: Ensure accurate calculation and timely remittance of required taxes to avoid penalties.
  2. Tax Planning and Assistance: Offer employees tax planning resources or consultations to help them understand the implications of exercising stock options.
  3. Section 83(b) Election: Employees might benefit from making a Section 83(b) election, which allows them to recognize income at the time of option grant rather than at exercise, potentially reducing taxes if the stock price is expected to rise significantly.


The tax implications of stock options are complex, requiring careful consideration by both employers and employees. Employers must understand their obligations regarding payroll taxes and the potential deductions available. By effectively managing these aspects, companies can maximize the benefits of offering stock options as part of their compensation packages, while ensuring compliance with tax regulations. Employees, on the other hand, should seek professional advice to navigate the tax implications of their stock options effectively.