The 15% discount math
A qualified ESPP under IRS Section 423 allows you to buy company stock at up to a 15% discount from the fair market value. With a lookback provision, the discount applies to the lower of the FMV at the start of the offering period or the FMV at the purchase date. Over a 6-month offering period, that produces a guaranteed minimum gross return of 17.6% if you sell same-day.
Why same-day sale is usually right
A disqualifying disposition (selling within 2 years of grant or 1 year of purchase) treats the discount as ordinary wage income, which is the same tax treatment as your W-2 wages. The arithmetic advantage of the qualifying disposition path (partial long-term gain treatment) is real but small, and you take on 12-24 months of concentrated-stock risk to capture it. For tech ESPP participants already concentrated in their employer's stock through RSU vests, the concentration cost typically outweighs the tax savings.
Colorado tax layer
Colorado taxes the ordinary discount income at up to 4.4% at the top bracket. That stacks on top of federal ordinary tax and Medicare. Your combined marginal on the discount income is approximately 40.8%.
Frequently asked
- Is a $27,500 ESPP contribution worth it in Colorado?
- At a 15% discount with a lookback, a same-day-sale strategy produces an after-tax return of approximately 10.4% per offering (~22.0% annualized). That's a risk-free return at the size of an emergency savings account yield. Maxing the contribution is almost always correct, subject to IRS $25k/year limit and plan-level percentage caps.
- Does Colorado tax ESPP discount income?
- Yes. On a same-day (disqualifying) sale, the full discount at purchase is ordinary wage income, taxed at your marginal federal rate plus 4.4% state. Medicare at 1.45% also applies.
- Should I hold past the qualifying disposition window?
- Holding two years from grant and one year from purchase (the qualifying disposition thresholds) shifts part of the gain from ordinary income to long-term capital gain. That saves tax, but only if the stock holds or rises. For most tech ESPP participants, same-day sale is correct: it locks in the discount and avoids concentration risk.
- What's the cap on ESPP participation?
- IRS Section 423 limits qualified ESPP purchases to $25,000 per year at FMV at the start of the offering period. Plans may also cap participation at 10-15% of wages. If the math above shows a contribution above those limits, treat the excess as illustrative only.
Related
- ESPP lookback calculator (model your specific plan)
- Colorado ESPP tax overview
- Complete ESPP maximization guide
Educational · 2025 · 15% discount, 6-month offering, same-day sale · Single filer at $250k base · Not tax advice