QSBS and OBBBA
For decades, forming a C-Corp was a binary bet on a specific timeline: The 5-Year Cliff.
Under the old rules, if you sold your company in Year 4 and 11 months, you received $0 in QSBS (Qualified Small Business Stock) benefits. You paid full taxes -- often double taxation -- without any of the reward.
The One Big Beautiful Bill Act (OBBBA), signed in July 2025, fundamentally changed this risk profile. By introducing a tiered vesting schedule and raising the exclusion cap, the legislation has made the C-Corp substantially less risky for founders who might exit early.
To see the practical impact, let's run a simulation for a hypothetical startup formed after August 1, 2025.
The Scenario
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Entity: A technology startup formed post-enactment (August 2025).
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The Exit: The founder sells the company for a $10 Million profit.
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The Comparison: We compare the Federal Tax Bill under three structures:
- LLC (Pass-Through): Taxed at standard Capital Gains rates (~23.8% incl. NIIT).
- Old C-Corp Rules: The pre-2025 "All or Nothing" rules.
- New C-Corp Rules (OBBBA): The new tiered exclusion and higher caps.
The Comparative Table: Federal Tax Liability on $10M Profit
| Exit Timing | LLC (Pass-Through) | C-Corp (Old Rules) | C-Corp (New OBBBA) | The "New Rule" Advantage |
|---|---|---|---|---|
| Year 3.5 | $2,380,000 | $2,380,000 | $1,190,000 | Saves $1.2M vs. LLC |
| Year 4.5 | $2,380,000 | $2,380,000 | $595,000 | Saves $1.8M vs. LLC |
| Year 5+ | $2,380,000 | $0 | $0 | Saves $2.4M vs. LLC |
Analysis of the Exits
Scenario A: The "Early" Exit (Year 3.5)
- The Old Problem: If you received an unsolicited offer after 3.5 years, the Old C-Corp rules punished you. You missed the 5-year window, so you paid full tax plus you likely dealt with corporate tax drag along the way.
- The New Reality: OBBBA introduces a 50% Exclusion for stock held between 3 and 4 years. Even though you sold early, you still cut your effective tax rate in half (from ~23.8% to ~11.9%).
- The Verdict: The C-Corp now beats the LLC even on a 3-year timeline.
Scenario B: The "Tweener" Exit (Year 4.5)
- The Old Problem: Selling just months before the 5-year mark used to be a tragedy. Founders would often try to delay deals to hit the deadline, sometimes killing the deal in the process.
- The New Reality: Stock held between 4 and 5 years now qualifies for a 75% Exclusion.
- The Verdict: You pay an effective federal rate of just ~6%. The "Risk of Ruin" for selling early has been effectively eliminated.
Scenario C: The "Grand Slam" (Year 5+)
- The Old Problem: The exclusion was capped at $10 Million. For a massive exit (e.g., $10M profit), you walked away tax-free, but any dollar over $10M was fully taxed.
- The New Reality: OBBBA raised the cap to $15 Million (indexed for inflation).
- The Verdict: The entire $10M gain is tax-free. And crucially, you have an extra $5 Million buffer for even larger exits before you pay a dime in federal tax.
The "Asset Cap" Buffer
There is one more structural advantage that isn't in the table but matters for growth.
- Old Rule: To issue QSBS, your company couldn't have gross assets over $50M.
- New Rule: The cap is raised to $75M.
- Practical Impact: You can now raise a significantly larger Series B or C round (up to $75M in gross assets) and still issue QSBS-eligible stock to new key hires. This allows you to keep your talent incentives tax-aligned for longer as you scale.
The Verdict: The Safe Zone Has Expanded
Before OBBBA, choosing a C-Corp was a gamble. You had to ask: "Am I 100% sure I will hold this for 5 years?" If the answer was no, the LLC was safer.
Now, the math has shifted.
- LLC: Still the correct choice for lifestyle businesses where you need immediate cash flow.
- C-Corp: Now the dominant choice for any company with a 3+ year horizon. The penalty for selling early (Years 3-5) has been reduced from "Total Loss" to "Partial Win."