Assignment history

Inventors

• Ian Shaeffer (presumably Rambus Inc.)
• Kyung Suk Oh (presumably Rambus Inc.)

The inventors, Ian Shaeffer and Kyung Suk Oh, were likely employed by Rambus Inc. at the time of the underlying application's priority date (December 21, 2006) and the patent's filing date (July 31, 2017), given that Rambus Inc. was the original assignee. The Google Patents record indicates an assignment from the inventors to Rambus Inc. was recorded on July 3, 2018. No unusual patterns, such as inventors departing the original assignee within 12 months of filing, are immediately apparent from the provided information.

Original assignee

The original assignee named on the issued patent is Rambus Inc..

Rambus Inc. operates with a hybrid semiconductor business model, selling high-value chips (e.g., DDR5 memory interface chips for servers) and licensing intellectual property (IP) for integration into other companies' chips. They are known for providing advanced technology solutions and holding a robust portfolio of over 1000 issued patents. Rambus is an operating company that ships products embodying its claims through its chip sales and also monetizes its IP through licensing. Its current status is operating, and it is a public company traded on NASDAQ (RMBS).

Assignment timeline

• 2009-12-08 (executed) / recorded 2018-07-03 — Reel 046262/0738

  • Conveyance: Assignment of Assignor's Interest
  • Assignor: Oh, Kyung S.; Shaeffer, Ian P. (Inventors)
  • Assignee: Rambus Inc.
  • Correspondent: Not specified in the provided data.
  • Context: Initial assignment of patent rights from inventors to the operating company.

• 2025-09-29 (executed) / recorded 2025-10-15 — Reel 073085/0650

  • Conveyance: Assignment of Assignor's Interest
  • Assignor: Rambus Inc.
  • Assignee: Signal LLP
  • Correspondent: Not specified in the provided data.
  • Context: Transfer of patent rights from an operating company to a likely non-practicing entity.

Timeline diagram

timeline
    title Ownership of US 10115439
    2006 : Priority date
    2017 : Filed by Rambus Inc
    2018 : Inventors assign to Rambus
    2018 : Patent granted
    2025 : Assigned to Signal LLP
    2026 : First infringement suit filed

NPE / troll-pattern signals

1. Shell-entity transfer — Present. The patent was transferred from Rambus Inc., an operating company, to Signal LLP. The "LLP" suffix often indicates a legal or investment entity rather than a product-producing company, and general searches for "Signal LLP" do not reveal a direct product-manufacturing business related to memory technology. Unified Patents, an anti-NPE organization, lists Signal LLP as a plaintiff in litigation involving this patent, reinforcing the likelihood that Signal LLP is a non-practicing entity. This transfer to a licensing-focused entity with no apparent products in commerce is a strong signal.

   • Citation: Reel 073085/0650, recorded 2025-10-15.

2. Known asserter in the chain — Present. The current assignee, Signal LLP, is identified by Unified Patents as actively engaged in patent litigation involving this patent, specifically noting a case filed in the Texas Eastern District Court. Unified Patents is an organization dedicated to deterring unsubstantiated or invalid patent assertions by Non-Practicing Entities (NPEs). Their identification of Signal LLP in litigation is a strong indicator that Signal LLP operates as a patent asserter.

   • Citation: "Current Assignee: Signal LLP" and "Family has litigation" with a link to a Texas Eastern District Court case filed by Unified Patents, as presented on the Google Patents page.

3. Repeat correspondent across the chain — Unclear. The provided patent text and Google Patents legal events do not explicitly state the name of the correspondent attorney or firm who filed the assignments for either recordation (Reel 046262/0738 and Reel 073085/0650). Therefore, it is not possible to assess whether the same correspondent recurs.

4. Cascading transfers — Not present. There are only two recorded assignments in the patent's history: from the inventors to Rambus and then from Rambus to Signal LLP. This does not constitute multiple consecutive assignments through chained LLCs in a short period.

5. Pre-litigation transfer — Present. The assignment from Rambus Inc. to Signal LLP was executed on September 29, 2025, and recorded on October 15, 2025 (Reel 073085/0650). A litigation case (2:26-cv-00093) involving this patent was filed in the Texas Eastern District Court in 2026. Given the current date (May 2026), this filing occurred within six months of the assignment, which is a strong signal for a pre-litigation transfer to enable assertion.

   • Citation: Reel 073085/0650, recorded 2025-10-15; Texas Eastern District Court case 2:26-cv-00093 filed in 2026.

6. Bankruptcy fire-sale — Not present. There is no information to suggest that Rambus Inc. filed for bankruptcy or that the patent was sold in bankruptcy proceedings.

7. Privateering — Present. Rambus Inc. is an operating company engaged in the semiconductor business. The patent was transferred from Rambus to Signal LLP, which appears to be a non-practicing entity engaged in assertion. This pattern is consistent with privateering, where an operating company transfers patents to an NPE that then asserts them against competitors, potentially benefiting the original operating company.

   • Citation: Reel 073085/0650, recorded 2025-10-15, showing transfer from Rambus Inc. to Signal LLP.

8. Defensive aggregator (anti-NPE) — Not present. The chain terminates with Signal LLP, which is identified as an asserter rather than a defensive aggregator like RPX or Unified Patents.

Verdict

NPE — high confidence. The patent was recently transferred from an operating company (Rambus Inc.) to Signal LLP (Reel 073085/0650, recorded 2025-10-15). This transfer occurred within six months of the first recorded infringement suit filed by Signal LLP in the Texas Eastern District Court (case 2:26-cv-00093, filed in 2026), strongly indicating a pre-litigation transfer to an assertion entity. Furthermore, Signal LLP is identified as a plaintiff in litigation by Unified Patents, an organization focused on countering NPE activity.

Verify on USPTO Assignment Center: https://assignmentcenter.uspto.gov/patent/index.html (Search by patent number 10115439).