The complaint
Dayal Family LLC v. Microsoft Corporation, No. 2:26-cv-00805 (E.D. Tex., Marshall Division), is a forty-five-page original complaint for patent infringement filed September 10, 2026, ECF No. 1, with a jury demand. Dayal, an Illinois limited liability company, alleges that it owns both patents by assignment from their sole inventor and that the patents share a common disclosure about naming expressions within a spreadsheet formula so that the names apply only within the cell where they are defined. The docket's assignment entry shows the case assigned to District Judge Rodney Gilstrap.
What the patents cover
U.S. Patent 12,541,642 has the same title as the '258 patent and issued February 3, 2026. Its claim 1 covers a method of creating a name within a formula in a spreadsheet or database cell by searching the formula for a unique symbol or combination of symbols, then finding an associated name and expression in the formula, equating the expression to the name to create a relationship, and using that relationship to evaluate other instances of the name in that cell but not in any other cell, where the formula refers to at least one other cell and the relationship's scope is limited to the first cell.
U.S. Patent 12,039,258, titled Method and system for dynamic naming of component expressions within a formula in a cell in a spreadsheet application, issued July 16, 2024. Its claim 1 covers a method of computing a formula in a cell of an electronic data processing application, selected from a database program, a project management program, a word processing program, and an electronic spreadsheet program, by searching the formula for a symbol that associates a name with an expression in the formula, assigning the name to the expression and its result, and using that result for later instances of the name in the formula, where the assignment applies only to that cell and has no relevance in any other cell that uses the same name.
What the lawsuit is about
Dayal alleges that the installed Excel application stored for download on Microsoft's servers and the web-based Excel application infringe through the LET() function. Count I alleges direct infringement of at least claim 10 of the '642 patent, Count II alleges induced infringement of at least claims 1 and 19 of the '642 patent, Count III alleges direct infringement of at least claim 20 of the '258 patent, Count IV alleges induced infringement of at least claims 1, 3, and 10 of the '258 patent, and Count V alleges willful infringement. For knowledge, the complaint alleges, on information and belief, that Dayal's patents and applications were cited against Microsoft's own patent filings, and it alleges that the inventor wrote to Microsoft in July 2019 about the provisional application before Microsoft launched LET(). The prayer asks for a judgment of infringement, a finding of willfulness, damages and enhanced damages, a permanent injunction, and attorneys' fees.
What to watch next
Microsoft's answer is due November 19, 2026 under an unopposed extension (ECF No. 8), and Judge Gilstrap set a scheduling conference for November 23, 2026 (ECF No. 15). Watch for Microsoft's answer or Rule 12 motion.