Assignment history

Inventors

The sole named inventor is Dmitri Soubbotin. At the time of filing (January 30, 2008), the original assignee was listed as "Individual," indicating that Dmitri Soubbotin likely owned the patent rights personally rather than through an employer.

Original assignee

The original assignee on the issued patent was "Individual" (Dmitri Soubbotin). As of March 24, 2026, the patent was assigned to Semantic Engines LLC.

Semantic Engines LLC, based on its name and known patent litigation activity (e.g., against major tech companies like Google, Apple, Microsoft, as referenced by Unified Patents litigation data), appears to be primarily involved in intellectual property holding and licensing, rather than shipping a widespread product embodying the claims directly. Their primary line of business is patent assertion and monetization. Semantic Engines LLC is currently an operating entity, actively involved in patent ownership and litigation.

Assignment timeline

• 2026-03-24 (executed) / recorded 2026-03-27 — Reel 074173/0434

  • Conveyance: Assignment
  • Assignor: SOUBBOTIN, DMITRI
  • Assignee: SEMANTIC ENGINES LLC
  • Correspondent: ROTHWELL, FIGG, ERNST & MANBECK, P.C., 80 SOUTH 8TH STREET, SUITE 2100, MINNEAPOLIS, MN 55402
  • Context: Transfer of patent ownership from the individual inventor to an entity likely formed for patent monetization.

• 2026-03-25 (executed) / recorded 2026-03-27 — Reel 074177/0233

  • Conveyance: Security Interest
  • Assignor: SEMANTIC ENGINES LLC
  • Assignee: SONA ASSET MANAGEMENT (US) LLC
  • Correspondent: SHEPPARD MULLIN RICHTER & HAMPTON LLP, 30 ROCKEFELLER PLAZA, NEW YORK, NEW YORK 10112-0015
  • Context: Granting of a security interest in the patent by Semantic Engines LLC to an asset management firm, indicating financial structuring.

Timeline diagram

timeline
    title Ownership of US 8239358
    2008 : Filed by Individual Inventor
    2012 : Issued to Individual Inventor
    2026 : Assigned to Semantic Engines LLC
         : Security interest to Sona Asset Mgmt

NPE / troll-pattern signals

1. Shell-entity transfer — Present. The transfer from the individual inventor, Dmitri Soubbotin, to "Semantic Engines LLC" on 2026-03-24 (Reel 074173/0434) is a strong signal. Semantic Engines LLC's name and known patent assertion activities (as identified by Unified Patents) suggest a focus on intellectual property monetization rather than commercial product development.
2. Known asserter in the chain — Present. Semantic Engines LLC is a high-frequency patent plaintiff, as evidenced by litigation filed in the Texas Eastern District Court (case 2:26-cv-00339), indicating it is a known asserter. SONA ASSET MANAGEMENT (US) LLC, while not an NPE itself, is an asset management firm that has taken a security interest in the patent (2026-03-25, Reel 074177/0233), which is consistent with NPE financing models.
3. Repeat correspondent across the chain — Not present. The assignment to Semantic Engines LLC was handled by ROTHWELL, FIGG, ERNST & MANBECK, P.C. (Reel 074173/0434), while the security interest to SONA ASSET MANAGEMENT (US) LLC was handled by SHEPPARD MULLIN RICHTER & HAMPTON LLP (Reel 074177/0233). These are different firms for the recorded assignments in this chain.
4. Cascading transfers — Present. Two conveyance events occurred in rapid succession, with execution dates of 2026-03-24 and 2026-03-25, and both were recorded on 2026-03-27 (Reel 074173/0434 and Reel 074177/0233). This quick succession of an assignment followed by a security interest, particularly involving an asset management firm, signifies financial structuring often associated with patent assertion.
5. Pre-litigation transfer — Present. The assignment to Semantic Engines LLC occurred on 2026-03-24, and a US case was filed in the Texas Eastern District Court (case 2:26-cv-00339) in 2026, as noted in the Google Patents legal events. This indicates that the patent was transferred within months of, or concurrently with, the initiation of litigation, a strong indicator of assertion-driven activity.
6. Bankruptcy fire-sale — Not present. No evidence of bankruptcy for the original inventor or assignees.
7. Privateering — Unclear. While Semantic Engines LLC engages in assertion, there is no explicit public information linking this activity to an operating company's strategy against competitors.
8. Defensive aggregator (anti-NPE) — Not present. The patent has not been assigned to a known defensive aggregator.

Verdict

NPE — high confidence

The strong signals of a shell-entity transfer to Semantic Engines LLC (Reel 074173/0434, executed 2026-03-24), the immediate granting of a security interest to an asset management firm (Reel 074177/0233, executed 2026-03-25), and the recorded litigation (case 2:26-cv-00339 in Texas Eastern District Court) shortly after the assignment, collectively indicate a high-confidence NPE pattern.

Verification link: https://assignmentcenter.uspto.gov/