S-1 Files S-1: RSU & Capital Gains Tax Exposure Calculator — Aug 21, 2026

What Changed

Aptevo Therapeutics filed an S-1 registration statement on August 21, 2026, signaling intent to go public. The filing size is 1 MB, which typically indicates a smaller biotech offering in the $50M to $150M range. For employees holding pre-IPO equity or investors considering allocation, this triggers a 180-day lockup clock and resets tax planning around restricted stock units.

The Numbers That Matter

Metric	Pre-IPO Private Shares	Post-IPO Liquid Shares	Tax Treatment Shift
Fair Market Value Basis	Board-determined (often 40% to 60% discount to IPO price)	Public offering price	AMT spread on ISO exercise now calculable
Liquidity Window	Zero (secondary restricted)	180 days post-effective date	Lockup expiration creates taxable event trigger
Tax Rate on Sale	37% ordinary income if RSUs vest within 12 months	20% long-term capital gains if held over 1 year from vest	17-point spread on $500K position equals $85K
Estimated Offering Range	Not disclosed in initial S-1	$50M to $150M typical for 1 MB filing	Dilution of 15% to 25% is standard

What This Means for Your Portfolio

If you hold $500K in pre-IPO Aptevo equity at the board-determined FMV, your post-IPO value depends on the offering price and lockup terms. Assuming a 20% pop on day one and a 180-day lockup, your $500K position could be worth $600K at lockup expiration, but you will owe ordinary income tax on the RSU vest date and capital gains tax on the appreciation from vest to sale. On a $600K sale after holding 13 months post-vest, your net proceeds are $494K after federal tax, assuming top bracket and long-term capital gains treatment.

Scenario Analysis

Position Size at FMV	IPO Day Value (20% pop)	Lockup Expiration Value (assumes 10% fade)	Net After-Tax Proceeds (LTCG)
$500K	$600K	$540K	$494K
$1M	$1.2M	$1.08M	$988K
$2M	$2.4M	$2.16M	$1.976M

This assumes you vest before the IPO, hold through lockup, and sell immediately after day 181. If you hold under 1 year from vest to sale, your effective tax rate is 37% ordinary income plus 3.8% NIIT, dropping net proceeds on a $500K position to $442K. A 13-month hold results in $52K higher net proceeds on a $500K position compared to an 11-month hold.

Additional Considerations

Aptevo's S-1 does not yet disclose underwriter names, share count, or price range. Those amendments typically arrive 2 to 4 weeks before the roadshow. If you are an employee with ISOs, your AMT calculation resets the moment the S-1 goes effective, because the spread between your strike price and the IPO price becomes a preference item. On a $500K ISO exercise at a $10 strike with a $20 IPO price, your AMT liability is $70K in the year of exercise, even if you cannot sell during lockup. This creates a cash flow trap unless you model the AMT credit carryforward.

For investors considering an IPO allocation, biotech offerings in this size range can experience significant volatility within 6 months. Your breakeven holding period is the point at which your long-term capital gains rate offsets the volatility drag. On a $1M allocation with a 20% day-one pop and a 20% six-month fade, you are flat at month 6, but your after-tax return turns positive only if you hold through month 13 and the stock recovers above $1.08M.

Frequently Asked Questions

Q: When does the 180-day lockup period start? A: The lockup starts on the IPO effective date, not the S-1 filing date, which is typically 4 to 8 weeks after the initial filing.

Q: How is the tax basis calculated for RSUs that vest before the IPO? A: Your basis is the fair market value on the vest date, which is the board-determined 409A price, not the IPO price.

Q: What happens to my AMT credit if I exercise ISOs before the IPO and the stock drops below my strike price? A: The AMT credit carries forward indefinitely, but you cannot recover the cash paid in the exercise year if the stock becomes worthless.

Q: When should I consider selling after lockup expiration? A: The tax consequences of your sale timing depend on your personal circumstances, including your holding period, cost basis, and market conditions. Consult a tax professional or financial advisor for guidance on your specific situation.

Run the Numbers

Use CalcMoney's Calculate Your After-Tax RSU Proceeds to see your exact figures under the current tax threshold and your specific lockup expiration date.

Disclaimer: This article is for informational purposes only and does not constitute professional financial, investment, tax, or legal advice. Please consult with a qualified financial advisor or tax professional before making any investment decisions related to IPO allocations, equity compensation, or tax planning strategies.

Run the Numbers: Capital Gains Tax Terminal on CalcMoney — see your exact figures under current market conditions.

Data sourced from SEC EDGAR S-1 Filings (IPO). Rates and thresholds are for informational purposes only. Consult a licensed financial advisor before making mortgage, investment, or tax decisions.

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