Timing
A reasonable royalty calculation must return to the date of first infringement.
The key element in setting a reasonable royalty after determination of validity and infringement is the necessity for return to the date when the infringement began.
— Panduit Corp. v. Stahlin Bros. Fibre Works, 575 F. 2d 1152, 1158 (Fed. Cir. 1978).
First infringement generally occurs on the first instance of the accused activity, or on the date of issuance of the patent-in-suit, whichever comes last.
Except as otherwise provided in this title, whoever without authority makes, uses, offers to sell, or sells any patented invention, within the United States or imports into the United States any patented invention during the term of the patent therefor, infringes the patent.
— 35 U.S. Code § 271 (a).
...a term beginning on the date on which the patent issues and ending 20 years from the date on which the application for the patent was filed in the United States...
— 35 U.S. Code § 154 (a)(2).
The date of first infringement is also known as the date of hypothetical negotiation. In multi-patent cases there may be more than one reasonable way to determine a date for hypothetical negotiation.
Use distinct dates for hypothetical negotiation for each claim at issue.
Here, because there are three different effective dates for the asserted claims, there are three different dates when DataQuill asserts that infringement began[.] … Therefore, there should be three different hypothetical negotiations.
— DataQuill Ltd. v. High Tech Computer Corp., 887 F. Supp. 2d 999, 1025 (S.D. Cal. 2011).
Use a single date for hypothetical negotiation covering all patents and claims.
It also makes sense that in each case there should be only a single hypothetical negotiation date, not separate dates for separate acts of infringement.
— LaserDynamics, Inc. v. Quanta Computer, Inc., 694 F. 3d 51, 76 (Fed. Cir. 2012).
A proper determination of the hypothetical negotiation date may be essential to an accurate calculation of damages.
We have explained that the correct determination of the hypothetical negotiation date is essential for properly assessing damages.
— LaserDynamics, Inc. v. Quanta Computer, Inc., 694 F. 3d 51, 75 (Fed. Cir. 2012).
The hypothetical negotiation date is generally distinct from the date where liability for infringement begins.
We have also been careful to distinguish the hypothetical negotiation date from other dates that trigger infringement liability. For example, the six-year limitation on recovery of past damages under 35 U.S.C. § 286 does not preclude the hypothetical negotiation date from taking place on the date infringement began, even if damages cannot be collected until some time later.
— LaserDynamics, Inc. v. Quanta Computer, Inc., 694 F. 3d 51, 75 (Fed. Cir. 2012).