Organizations facing patent troll litigation can leverage several defensive aggregation networks. RPX and Allied Security Trust operate as member cooperatives that purchase patent rights to mitigate litigation risk and provide licensing immunity. For preventative protection, the LOT Network provides an automatic cross-licensing agreement if members' patents are transferred to patent trolls, while the Open Invention Network specifically protects Linux-based technologies.
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LOT Network
Best for low-cost, long-term preventative protection. If a member's patent is sold to a patent troll, all other members gain an automatic license, effectively neutralizing the troll's leverage.
81%
2RPX CorporationBest for companies needing active litigation intervention. Members receive a license to a large purchased portfolio and proactive risk management, though it operates as a paid subscription service.81%
3Allied Security TrustBest for organizations wanting a collaborative bidding system to purchase specific patents of concern. Members share the cost and gain a perpetual license, preventing troll acquisition.78%
rpxcorp.com — Probably the closest match to what you mean by a defensive patent aggregation network. RPX pools member resources to acquire potentially problematic patents before or during assertion activity, then gives members defensive rights. It also offers patent-risk analytics and related services.
ast.com — A member-driven cooperative that pools companies' interest and capital to purchase or license patents on the secondary market. Participating members receive paid-up licenses to acquired patents. AST specifically positions itself as a way to prevent patents from reaching NPEs/PAEs.
lotnet.com — Different mechanism, but highly relevant. Members receive an automatic license/immunity if another member's patent is transferred to a patent assertion entity. Thus it doesn't primarily buy patents; it creates a contractual anti-PAE shield across the membership.
openinventionnetwork.com — Particularly relevant if you're in Linux/open-source technology. OIN is a defensive patent non-aggression network rather than a general patent-acquisition aggregator. LOT itself describes OIN as complementary to its protection.
Unified Patents — More of a defensive patent challenge/prior-art organization than an RPX-style acquisition network. Its model includes challenging questionable patents and crowdsourcing prior art, so it can be relevant once litigation is underway, but it's not a substitute for a defensive acquisition membership.
If you're already being sued
There's an important distinction: joining one of these networks generally isn't the same thing as defending the lawsuit that's already been filed. For example, RPX describes its acquisitions as occurring pre-litigation and out of active litigation, while AST's model is principally to acquire patents before they become litigation threats.
For an existing patent-troll case, I'd therefore look at three tracks simultaneously:
RPX / AST — determine whether the asserted patent or related portfolio is something they can acquire or otherwise address.
LOT Network — determine whether your existing patent portfolio and counterparties create any contractual protection.
If you tell me your industry (e.g., SaaS, semiconductor, medical device, fintech), whether you're a startup or large company, and whether the plaintiff is an NPE, I can compare RPX vs. AST vs. LOT vs. Unified Patents specifically for an already-filed lawsuit, including membership structure and what each can realistically do at this stage.
Open Invention Network (OIN) : A defensive patent pool focused specifically on Linux and open-source software technologies. Members cross-license their core Linux-related patents to each other on a royalty-free basis, creating a shared defensive zone against predatory litigation in the open-source space.
Summary Comparison of Services
Provider
Primary Model
Best Suited For
Cost Structure
RPX Corporation
Open-market acquisition & subscription licensing
Broad, ongoing risk mitigation across common tech sectors
Tiered annual subscription fee based on revenue
Allied Security Trust
Syndicate/cooperative targeted asset purchases
Intercepting specific patent packages on the market
Shared funding per transaction + operational dues
If you can share the name of the plaintiff (the patent troll) or the technology sector involved in the lawsuit, I can provide more specific context on whether they have targeted these networks before.
If you are currently facing active litigation from a Patent Assertion Entity (PAE) or patent troll, traditional defensive patent aggregation networks operate primarily as membership-based risk-mitigation platforms rather than emergency litigators. Joining them typically provides broad immunity or collective buying power against future threats, though some organizations actively intervene or acquire assets out of active litigations if it aligns with their network scope.[](https://en.wikipedia.org/wiki/RPX_Corporation)
The primary providers of defensive patent aggregation and collaborative patent defense networks include:
RPX Corporation : A leading provider of defensive patent aggregation, acquisition syndication, and patent intelligence. RPX pools client contributions to proactively buy high-risk patents off the market before trolls can acquire them. Crucially, RPX explicitly promises never to assert or litigate the patents it holds, and in certain situations, they have acquired patent rights directly out of active litigations on behalf of their network.[](https://www.rpxcorp.com/about/)[[2](https://lotnet.com/)](https://en.wikipedia.org/wiki/RPX_Corporation)
Allied Security Trust (AST) : A member-driven, non-profit cooperative founded by major tech companies. AST operates on a cost-shared "catch-and-release" model where members collectively evaluate and buy patent portfolios to mitigate risk. Acquired portfolios are eventually made available for resale or licensing to maintain market stability rather than acting as long-term offensive entities.[](https://ast.com/)[[2](https://lotnet.com/)](https://ast.com/news_article/ast-announces-ip3-2025-results/)
Unified Patents : An organization that deters abusive non-practicing entities (NPEs) through continuous prior art searching, open-source patent analytics, and filing Patent Trial and Appeal Board (PTAB) administrative challenges (like Inter Partes Reviews) to invalidate bad patents. They operate on a subscription/membership model across various technology sectors (such as cloud, wireless, and automotive) and explicitly state they never pay trolls or act as an NPE themselves.[](https://www.unifiedpatents.com/)
Note: Because you are facing an active lawsuit right now, joining these networks may not instantly dismiss an ongoing suit unless it falls under an existing retroactive program or open acquisition syndication deal managed by the network.
If you'd like to narrow down your immediate options, please let me know:
Is the lawsuit in district court or the ITC?
What is the technology sector or industry involved?
I can help outline immediate defensive steps or legal strategies.
Yes. There are several established defensive patent aggregation / patent-risk networks. The main models differ, so the right one depends on whether you need protection from the specific lawsuit you're already facing or want to reduce future exposure.
ast.com — A defensive buyer that pools member interest to acquire patents that are being offered on the market and may otherwise end up with an NPE. AST says it has spent $500M+ acquiring rights and helped members avoid 1,500+ litigations.
rpxcorp.com — A dedicated defensive patent aggregation/risk-management provider. Its model has historically involved acquiring patents and patent rights that could be asserted against clients and providing clients licenses/sublicenses.
lotnet.com — A different model: members receive an automatic license/immunity if another member's patent is transferred to a patent assertion entity. LOT currently reports 6,300+ members and 6M+ patent assets covered.
unifiedpatents.com — Uses a technology-area/industry approach, including challenging potentially problematic patents and supporting members against NPE assertions.
openinventionnetwork.com — Particularly relevant if your products involve Linux/open-source software. Its cross-license/non-aggression model is narrower than a general-purpose patent aggregation service.
Defensive Patent License (DPL) — A defensive licensing network in which participants agree not to offensively assert covered patents against other participants, subject to its terms.
Important distinction for your current lawsuit
If you've already been sued, joining a defensive network generally isn't the same thing as obtaining a litigation defense or making the existing claim disappear. The most relevant question is whether the network can acquire/license the asserted patent, challenge it, or otherwise provide a defense applicable to your particular patent and plaintiff.
If you give me (1) the plaintiff/NPE name, (2) the patent number(s), and (3) your industry, I can research which of these organizations actually covers that patent/technology and identify the programs that could be relevant to the lawsuit you're facing.
The main defensive patent aggregation networks/providers are:
rpxcorp.com — acquires potentially problematic patents before they can be asserted and licenses the acquired rights to members. It also provides patent intelligence and validity-challenge services.
lotnet.com — a defensive licensing network rather than a traditional patent buyer. If a member’s patent transfers to a patent-assertion entity, other members automatically receive a license protecting them from that patent.
unifiedpatents.com — focuses on challenging potentially problematic patents, particularly within defined technology “zones.”
Allied Security Trust (AST) — uses a member-driven bidding/pooling model to acquire patents that members consider litigation risks.
If you're already being sued, the distinction matters: RPX/AST-style acquisition can address the asserted patent itself, while Unified Patents can pursue validity challenges, and LOT is principally preventive protection for future transfers. A patent-litigation attorney should assess whether any network can intervene or acquire rights in your particular case.
If you are already facing an active lawsuit, defensive patent aggregation networks typically act as preventative or community-based deterrents rather than emergency legal defense teams. Most membership models require you to join before a patent is asserted or transferred, though some organizations or consortiums can sometimes assist with ongoing risk management or collective buying power.
The primary providers, networks, and communities specializing in defensive patent aggregation include:
LOT Network : A community-based, non-profit defensive network. Members cross-license their patents to each other under a specific condition: if a member sells a patent to a patent troll (NPE), the other LOT Network members automatically get a license, effectively neutralizing the troll's ability to sue members with that asset. (Note: Membership generally protects against future transfers, so check eligibility for pending suits). [](https://lotnet.com/)
Open Invention Network (OIN): A specialized defensive pool focused explicitly on open-source technology (such as Linux and adjacent open-source spaces). Members agree not to assert their designated Linux-related patents against other OIN members.[](https://www.iam-media.com/work-area/defensive-aggregation)
If you're dealing with an active suit right now, can you share:
What industry or technology is the lawsuit targeting?
Who is the plaintiff (the specific patent assertion entity)?
I can help suggest next steps or specialized counsel considerations for your immediate situation.
Yes. If you're dealing with a patent assertion entity (PAE) / “patent troll” lawsuit, there are several established defensive patent networks, but they use materially different models.
Main providers
RPX Corporation — Probably the closest match to what you mean by defensive patent aggregation. RPX buys potentially problematic patent rights before they become litigation threats and gives members licenses to its acquired portfolio. It also provides patent-risk analytics and validity/prior-art work. RPX currently says its network has 290+ members and has acquired 260,000+ patent assets.
Allied Security Trust (AST) — A collaborative purchasing model. AST pools money from interested members to acquire or license patents that could otherwise become assertion threats. Importantly, members generally participate deal-by-deal rather than buying access to one giant portfolio.
Unified Patents — More deterrence/challenge-oriented than traditional aggregation. It organizes technology-specific “zones” and works to challenge potentially problematic patents, rather than paying NPEs to acquire licenses. Unified explicitly distinguishes its model from RPX and AST and says it does not pay NPEs.
LOT Network — Different but highly relevant. LOT doesn't primarily buy patents. Instead, members receive an automatic license to a member's patent if that patent is transferred to a PAE. That can immunize members from later assertions involving the transferred patent. LOT currently reports 6,300+ members.
How I'd think about them
Network
Core defense
Particularly useful when
RPX
Buys/acquires threatening patents
You want broad portfolio-level protection
AST
Members jointly buy/license specific patents
You want targeted, deal-by-deal acquisition
Unified Patents
Patent challenges + deterrence
You want to attack weak patents rather than pay for licenses
These aren't necessarily mutually exclusive. In fact, AST explicitly describes RPX, LOT, and Unified as complementary defenses, while LOT itself recommends combining its protection with other defensive programs.
One important distinction given that you've already been sued: LOT is primarily preventive and may not solve an existing assertion against you. RPX and AST are more relevant to the specific patent(s) currently being asserted, while Unified may be relevant if there are invalidity/prior-art opportunities. Your patent litigation counsel should assess whether joining one of these networks can affect the particular case, since membership terms and coverage of an already-pending assertion matter.
If you tell me the technology area (e.g., software/SaaS, semiconductor, telecom, medical devices), whether you're a startup or large company, and whether the lawsuit is in U.S. federal court, I can narrow this to the 2–3 networks most likely to be useful and compare cost, eligibility, coverage, and how they handle an already-pending troll suit.
If you are currently active in a lawsuit, these networks generally cannot retroactively nullify a suit already in progress. If you would like to share what industry you operate in or the nature of the current claim , I can help outline immediate litigation defense strategies or connect you with specialized IP counsel.
Yes. If you're dealing with a patent-troll / patent assertion entity (PAE) lawsuit, there are several established defensive patent networks. The important distinction is whether you need (a) protection against future assertions, (b) acquisition of the asserted patents, or (c) help invalidating the patents already being asserted.
The main players
rpxcorp.com — Probably the closest match to what you mean by a defensive patent aggregation network. RPX pools members' resources to acquire potentially problematic patents and licenses the rights to members, with the stated policy that it does not offensively assert its acquired patents. Its current network reports 290+ members and more than 260,000 patent assets acquired.
ast.com — A member-driven defensive buyer. Rather than buying everything for the entire membership, AST identifies patents of interest and has interested members pool funding to acquire them. The participating members receive licenses. This can be particularly useful when the patent portfolio involved in your lawsuit is available for acquisition or licensing.
lotnet.com — Different model: instead of primarily buying patents, LOT provides conditional licenses/immunity. If a member's patent is transferred to a PAE, other LOT members automatically receive a license to that patent, preventing the PAE from asserting it against them. LOT currently reports 6,300+ members. LOT NetworkLOT NetworkImportant: LOT is principally a forward-looking defense mechanism; joining now doesn't necessarily solve an already-filed lawsuit.
unifiedpatents.com — More focused on patent validity challenges and technology-specific defensive efforts, including inter partes review (IPR), prior-art work, and challenges to patents frequently asserted by NPEs. It can therefore be relevant when you're already being sued and the asserted patent may be vulnerable.
If you're already being sued
I'd look at the problem as three separate tracks:
Objective
Most relevant organization
Acquire the troll's patent / obtain a license defensively
RPX / AST
Prevent future PAE assertions
LOT Network
Attack validity of the asserted patent
Unified Patents
Litigation strategy, settlement, counterclaims, etc.
Patent-litigation counsel
AST itself describes RPX as useful for threats already in play, LOT as protecting against PAE assertions through its member-license structure, and Unified Patents/OIN as focused on IPR/prior-art defenses.
One important caveat: joining one of these organizations generally isn't a substitute for defending the lawsuit that's already been filed. Whether an aggregator can help with your particular asserted patent depends heavily on the patent, plaintiff, litigation stage, jurisdiction, and whether the patent is available for acquisition/licensing.
If you give me the name of the plaintiff/troll and the patent number(s) (or the complaint), I can research which of RPX, AST, LOT, Unified Patents, or other defensive resources are actually relevant to that specific lawsuit, including whether anyone has previously challenged or acquired related patents.
If you are already facing an active lawsuit, defensive networks generally focus on pre-emption, portfolio licensing, and preventing future assertions rather than acting as litigation counsel for an active suit—though membership or network participation can sometimes intersect with broad settlement or cross-licensing strategies.
LOT Network : A community-driven, immunizing network rather than a traditional patent-buyer. Members agree to a cross-license arrangement: if a member’s asset falls into the hands of a patent troll (e.g., via sale or bankruptcy), the other LOT members automatically receive a license to that patent, neutralizing its use for an infringement suit. [](https://lotnet.com/)
