What the Federal Circuit’s Poultry Patent Ruling Says About 'About'

Why It Matters

The decision injects uncertainty into patents that rely on vague degree terms, potentially lowering their enforceability and market value in licensing, M&A, and financing transactions.

Key Takeaways

• Federal Circuit upheld indefiniteness risk for “about” without clear support
• Approximation language can lower patent portfolio valuation in M&A due diligence
• Consistent specification examples essential to defend flexible claim scope
• Defining “about” with explicit tolerance strengthens enforceability and licensing
• Tiered claims combine broad “about” language with precise dependent limits

Pulse Analysis

Approximation language has long been a double‑edged sword in patent drafting. Terms like “about” or “approximately” let inventors capture real‑world variability without pinning down exact numbers, which can be advantageous in fast‑moving tech sectors. The Federal Circuit’s May 4 ruling, however, draws a hard line: such language is only defensible when the specification, examples, and prosecution history collectively explain the intended tolerance. By highlighting inconsistencies in the Enviro Tech record, the court reinforced the indefiniteness doctrine and reminded practitioners that flexibility must be grounded in concrete technical support.

For businesses, the practical fallout is immediate. Patent assets are routinely valued on the basis of claim breadth and enforceability; vague degree terms now introduce a quantifiable risk that can depress valuation in due‑diligence reviews, merger negotiations, and licensing deals. A portfolio that appears broad because of “about” language may be deemed unstable if the underlying record fails to define the term, prompting investors to demand discounts or additional warranties. Moreover, freedom‑to‑operate analyses become more complex, as competitors must assess whether their products fall within an undefined tolerance, potentially prompting costly design‑around efforts.

Counsel can mitigate these risks through disciplined drafting and prosecution. Defining “about” with a specific percentage, deviation, or industry‑standard range in the specification provides an objective anchor that courts can rely on. Tiered claiming—using a broad independent claim with “about” and tighter dependent claims with precise limits—creates a safety net if the broader language is challenged. Consistency across examples and clear explanations of any variance, supported by expert declarations when necessary, further strengthens the claim’s defensibility. By aligning prosecution arguments with future enforcement strategies, practitioners can preserve the commercial advantages of flexible language while minimizing indefiniteness exposure.