Panduit Test

The Panduit test is the dominant framework for proving lost profits as patent damages under 35 U.S.C. § 284: ORIGIN: Panduit Corp. v. Stahlin Bros. Fibre Works, Inc. (6th Cir. 1978): the Sixth Circuit established four factors that a patent owner must prove to recover lost profits; the Federal Circuit subsequently adopted the Panduit test; FOUR FACTORS: (1) DEMAND for the patented product — the market wanted a product with the patented features; (2) ABSENCE OF ACCEPTABLE NON-INFRINGING SUBSTITUTES — customers had no alternatives that would have satisfied their demand without practicing the patent; (3) MANUFACTURING AND MARKETING CAPACITY — the patent owner had the capability to produce and sell the additional units to meet that demand; (4) AMOUNT OF LOST PROFIT — the specific dollar amount of profit the patent owner would have made on those additional sales; LEGAL STANDARD: if the patent owner proves all four factors by a preponderance of the evidence, it is entitled to lost profits — the profits it would have made but for the infringement; RELATIONSHIP TO 'BUT FOR' CAUSATION: the Panduit test implements the general 'but for' causation requirement from Rite-Hite Corp. v. Kelley Co. (Fed. Cir. 1995): the patent owner must show what would have happened but for the infringement; Panduit is a proxy for 'but for' causation — if all four factors are met, it is reasonable to conclude the patent owner would have made those sales.

Factor 1 — DEMAND FOR THE PATENTED PRODUCT: (1) WHAT MUST BE SHOWN: customers wanted a product that embodies the patented features; the demand need not be specifically for the 'patented' features — it is sufficient to show demand for the product that uses the patented technology; (2) EVIDENCE TYPES: sales volume of the accused product (showing customers actually bought a product using the patent); customer surveys or testimony about why they purchased the product; market analysis showing demand trends for products with the patented features; expert testimony on market conditions; (3) INFRINGER'S SALES AS EVIDENCE: the infringer's own sales are strong evidence of demand — if customers bought the infringing product, there was demand; (4) COMMON GROUND: Factor 1 is rarely seriously disputed when the infringer actually sold significant quantities of the accused product — the infringer's sales volume is generally treated as sufficient evidence of market demand; (5) NUANCE — DEMAND FOR PATENTED FEATURE vs. ENTIRE PRODUCT: the Federal Circuit requires that demand be for the patented features specifically; if customers buy the product for other unrelated reasons and the patented feature is a minor or unused component, Factor 1 may be harder to establish; this connects to the apportionment requirement — demand must be tied to the patented contribution.

Factor 2 is typically the most contested Panduit factor — defendants almost always argue that acceptable non-infringing substitutes existed: WHAT IS AN 'ACCEPTABLE' SUBSTITUTE: a non-infringing alternative that customers would have found acceptable — meaning they would have purchased it instead of the patent owner's product IF the infringing product were not available; the substitute need not be identical; it must satisfy the relevant customer demand; IMPORTANT CAVEAT: the substitute must be NON-INFRINGING (not practicing the patent) and must actually be AVAILABLE in the market during the infringement period; THEORETICAL vs. AVAILABLE SUBSTITUTES: a substitute that could have been made (hypothetically) but was not actually manufactured and available for sale during the infringement period does NOT constitute an acceptable non-infringing substitute (Grain Processing v. American Maize, Fed. Cir. 1999); the infringer had an incentive to design around and build an alternative — but if it chose not to, the question is whether other available alternatives existed; PROVING ABSENCE OF SUBSTITUTES: patent owner typically shows: (1) no competing products existed in the relevant market that lacked the patented technology; (2) available alternatives were technically inferior or lacked a key attribute customers demanded; (3) customers actually chose the patented product over alternatives (choice data); CONTESTING FACTOR 2: defendants submit evidence of: existing competing products the patent owner classifies as substitutes; technical explanations of why the competing products satisfy the same functional need; market share data showing customers' willingness to choose competing products; availability of design-around alternatives.

FACTOR 3 — MANUFACTURING AND MARKETING CAPACITY: (1) WHAT MUST BE SHOWN: the patent owner had the ability to produce additional units to satisfy the demand that the infringer captured; (2) EVIDENCE: production capacity reports, factory utilization data, supply chain capability, historical production ramp-up rates; if the factory was operating below capacity, the incremental units could have been produced without new investment; (3) MARKETING CAPACITY: the patent owner had the sales force, distribution channels, and customer relationships to make those additional sales; (4) START-UP/SMALL COMPANY CONTEXT: a startup or small company may not have had the physical capacity to match the infringer's volume; courts may still award some lost profits for the units the patent owner could have produced and sold, even if it couldn't have captured the infringer's full volume; (5) PARTIAL LOST PROFITS: if Factor 3 is only partially satisfied (patent owner could have sold 60% of what the infringer sold), lost profits are apportioned accordingly; FACTOR 4 — AMOUNT OF LOST PROFIT: (1) WHAT MUST BE SHOWN: the specific profit per unit the patent owner would have made; (2) CONTRIBUTION MARGIN: most courts use the incremental (contribution) margin — net sales price minus variable costs (costs that increase when an additional unit is produced); fixed costs are generally excluded because they do not increase with additional sales; (3) PRICE ELASTICITY: if the market is price-sensitive, additional units might require price reductions; Factor 4 analysis may need to account for this; (4) INCREMENTAL COSTS: only costs that change with additional volume count against the profit margin (material, labor, shipping) — not allocated overhead from fixed costs.

When a patent owner cannot satisfy Panduit Factor 2 (acceptable non-infringing substitutes DO exist), it may use the MARKET SHARE APPROACH as an alternative: GRAIN PROCESSING APPROACH (Fed. Cir. 1999): the patent owner can recover lost profits in proportion to its market share even when Factor 2 fails — if non-infringing alternatives would have filled part of the demand, the patent owner would still have captured its proportionate share; MATHEMATICAL STRUCTURE: patent owner's market share = X%; if infringer sold N units, patent owner would have captured X% × N units; lost profits = X% × N units × profit per unit; EVIDENCE REQUIRED: reliable market share data for the patent owner during the relevant period; market analysis showing the patent owner competed in the same market as the infringer; reliable profit per unit figures; MULTIPLE SELLERS: if there were 4 sellers (patent owner + infringer + 2 others), each with 25% market share, the patent owner would have captured 25%/(25%+25%+25%) = 33% of the infringer's sales (its proportionate share of the non-infringing market); COMPARING TO PANDUIT: Panduit (if all 4 factors met): patent owner gets 100% of the infringer's sales as lost profits; market share approach: patent owner gets its proportionate market share of the infringer's sales; COMBINATION: some patent owners use Panduit for units sold to its existing customers (those that specifically wanted the patent owner's product) and the market share approach for units sold to customers who would have accepted any available alternative.