Patent Troll

A patent troll is a person or company that acquires patents not to develop or commercialize an invention, but solely to demand licensing fees or file infringement lawsuits against businesses that are actually producing goods or services. The term is informal and pejorative; the neutral legal equivalents are non-practicing entity (NPE) and patent assertion entity (PAE).

How a patent troll works

A patent troll acquires patents, often purchased cheaply from bankrupt companies, individual inventors, or patent brokers, with no intention of building a product around them. It then identifies businesses whose products or processes could plausibly be argued to infringe those patents and sends demand letters threatening litigation unless the target pays a licensing fee or enters into a settlement.

Most targets settle rather than fight. Patent litigation defense costs can reach millions of dollars, so a settlement demand of $50,000–$200,000 is often cheaper to accept than to contest, regardless of whether the claim has merit.

Key characteristics

• No products or services: The entity does not manufacture, sell, or develop any products or services covered by its patents.
• Litigation as a business model: Revenue comes from licensing fees and lawsuit settlements, not from commercializing inventions.
• Broad or vague patent claims: Asserted patents often have wide, ambiguous claims that can be stretched to cover many technologies or processes.
• Volume targeting: Demand letters are frequently sent to dozens or hundreds of companies simultaneously.
• Settlement pressure: Demands are calibrated to be cheaper to settle than to litigate.

Patent troll vs. legitimate patent licensing

Not every entity that licenses patents without manufacturing products is a patent troll. Universities, research institutions, and individual inventors frequently license patents to generate revenue from genuine innovations—a practice that is both legal and economically valuable.

The distinction lies in intent and conduct. A legitimate licensor holds patents on real inventions and seeks fair compensation for their use. A patent assertion entity typically acquires patents opportunistically, asserts them broadly, and relies on litigation cost asymmetry rather than claim merit to extract payment.

Protections and defenses

The America Invents Act (AIA) of 2011 created the Inter Partes Review (IPR) process, which allows companies to challenge a patent's validity before the United States Patent and Trademark Office’s (USPTO's) Patent Trial and Appeal Board (PTAB) at significantly lower cost than federal court litigation. The Supreme Court's Alice Corp. v. CLS Bank International (2014) decision also narrowed the patentability of abstract software concepts, limiting some of the broadest NPE claims.

Businesses can take proactive steps to reduce exposure:

• Conduct a freedom-to-operate analysis before launching a product to identify potential patent conflicts.
• Monitor patent assignment records to identify entities acquiring patents in relevant technology areas.
• Consult a patent attorney promptly upon receiving a demand letter: do not ignore it or respond without legal guidance.

Related terms

• Patent: The foundational IP right that patent trolls exploit
• Patent infringement: The legal claim at the center of most patent troll demands
• Intellectual property: The broader legal framework governing patents, trademarks, and copyrights

FAQs about patent troll

Is patent trolling illegal?

No. Patent assertion entities operate entirely within the legal system, exploiting litigation costs rather than breaking any law. Some states have enacted bad-faith demand letter statutes that can penalize particularly abusive conduct, but the core practice remains lawful at the federal level.

Why do patent trolls target small businesses?

Large corporations have in-house legal teams, patent portfolios for cross-licensing leverage, and resources to fight claims at trial. Small businesses and startups often lack the cash reserves to absorb even a modest legal defense, making a below-litigation-cost settlement demand far more likely to succeed.

What should a business owner do after receiving a patent demand letter?

Consult a patent attorney before responding or acknowledging the claim in writing, since even an informal reply can create legal exposure. An attorney can assess whether the patent is valid, whether your product actually falls within its claims, and whether an Inter Partes Review challenge at the PTAB is a viable path forward.