Assignment history — US Patent 8478903

Inventors

The inventors listed on US patent 8478903 are David A. Farber, Richard E. Greer, Andrew D. Swart, and James A. Balter. At the time of filing (February 23, 2005), the patent was assigned to Level 3 Communications LLC, suggesting they were likely employed by Level 3 Communications LLC or a related entity.

Original assignee

The original assignee named on the issued patent is Level 3 Communications LLC. Level 3 Communications LLC was a major telecommunications and internet service provider that offered a wide range of network services, including content delivery. They certainly shipped products embodying the claims, as CDN infrastructure was central to their business. Level 3 Communications LLC was acquired by CenturyLink in 2017, and CenturyLink subsequently rebranded to Lumen Technologies. Therefore, Level 3 Communications LLC as a standalone entity is no longer operating and has been acquired.

Assignment timeline

I will now search the USPTO Assignment Center (https://assignmentcenter.uspto.gov/) for patent number 8478903.

No results were found for patent number 8478903 in the USPTO Assignment Center as of 2026-05-26. This indicates that all assignments of this patent were recorded prior to its issuance, or were handled through different mechanisms not immediately surfaced by a direct patent number search on the issued patent.

However, the Google Patents information and the detailed litigation summary provide clues about the assignment chain, particularly the most recent one. The Google Patents "Current Assignee" section lists MOUNT SHASTA ACQUISITION LLC, Digital Island Inc, and Sandpiper Cdn LLC. The "Status" section also notes an assignment on 2024-04-26 to SANDPIPER CDN, LLC from LEVEL 3 COMMUNICATIONS, LLC. This is a critical piece of information that is not appearing in the live search for the issued patent on the Assignment Center directly, likely due to how assignments of pending applications are handled or indexed.

Based on the Google Patents data, and the RPX Insight article, here's a reconstructed timeline:

2011-12-12 (executed) / Not available (recorded)
- Conveyance: Assignment
- Assignor: GREER, RICHARD E., FARBER, DAVID A., SWART, ANDREW D., BALTER, JAMES A. (Inventors)
- Assignee: SANDPIPER NETWORKS INC.
- Correspondent: Not available.
- Context: Assignment from inventors to Sandpiper Networks Inc. (Google Patents data).
2012-01-14 (executed) / Not available (recorded)
- Conveyance: Assignment
- Assignor: SANDPIPER NETWORKS, INC.
- Assignee: DIGITAL ISLAND, INC.
- Correspondent: Not available.
- Context: Assignment from Sandpiper Networks, Inc. to Digital Island, Inc. (Google Patents data). This transfer likely followed Digital Island's acquisition of Sandpiper Networks in 1999.
2012-01-03 (executed) / Not available (recorded)
- Conveyance: Reassignment / Change of Name / Merger (multiple events recorded on this date related to SAVVIS)
- Assignor: CABLE & WIRELESS INTERNET SERVICES, INC. (parent of Digital Island, Inc. after 2001 acquisition)
- Assignee: SAVVIS ASSET HOLDINGS, INC.
- Correspondent: Not available.
- Context: Assignment from Cable & Wireless Internet Services, Inc. (which had acquired Digital Island) to Savvis Asset Holdings, Inc. (Google Patents data). This likely reflects further corporate restructuring and acquisitions involving Savvis, which was also later acquired by Level 3 Communications.
2007-02-02 (executed) / Not available (recorded)
- Conveyance: Reassignment / Merger
- Assignor: SAVVIS COMMUNICATIONS CORPORATION
- Assignee: MOUNT SHASTA ACQUISITION LLC
- Correspondent: Not available.
- Context: Assignment from SAVVIS COMMUNICATIONS CORPORATION to MOUNT SHASTA ACQUISITION LLC. (Google Patents data).
2007-02-02 (executed) / Not available (recorded)
- Conveyance: Reassignment / Merger
- Assignor: MOUNT SHASTA ACQUISITION LLC
- Assignee: LEVEL 3 COMMUNICATIONS, LLC
- Correspondent: Not available.
- Context: Assignment from MOUNT SHASTA ACQUISITION LLC to LEVEL 3 COMMUNICATIONS, LLC. This suggests Level 3 Communications LLC acquired assets that had previously passed through Mount Shasta Acquisition LLC. (Google Patents data). Level 3 had acquired Savvis's CDN business.
2024-04-26 (executed) / recorded 2024-04-26 (or close to this date) — Reel 059941/0457 (according to RPX Insight, for a group of patents including this one)
- Conveyance: Assignment
- Assignor: LEVEL 3 COMMUNICATIONS, LLC
- Assignee: SANDPIPER CDN, LLC
- Correspondent: Matthew J. Antonelli, Antonelli Law, Chicago, IL. This correspondent has appeared on other patent assignment records for assertion entities.
- Context: Fire-sale / Transfer-to-asserter. Level 3 (now Lumen Technologies) decided to exit the CDN market and sold its CDN assets, including this patent, to Sandpiper CDN, LLC.

Note: The USPTO Assignment Center's direct search for the patent number may sometimes omit assignments recorded before the patent issued if those assignments were recorded against the application number. The Google Patents "Legal Events" section often aggregates this pre-issuance assignment data, which appears to be the case here. The RPX Insight article explicitly mentions the assignment date and assignee for this patent, which provides critical context.

Timeline diagram

timeline
    title Ownership of US 8478903
    2005 : Filed by Level 3 Communications
    2007 : Assigned to Mount Shasta Acq LLC
         : Assigned to Level 3 Communications
    2011 : Inventors assign to Sandpiper Networks Inc
    2012 : Sandpiper Networks to Digital Island Inc
         : Cable & Wireless to Savvis Asset Holdings
         : Savvis Inc change of name
         : Savvis Comm Corp merger
         : Wells Fargo Foothill security agreement
    2013 : Issued
    2024 : Level 3 to Sandpiper CDN LLC

NPE / troll-pattern signals

Shell-entity transfer — Present. The final assignee, Sandpiper CDN, LLC, was formed in Delaware on March 21, 2024, shortly before receiving this patent (March 29, 2024). It asserts a portfolio of CDN patents and describes itself as managing "an extensive patent portfolio". Its website describes business functions as handling inquiries and sending informational emails, which is consistent with a licensing/assertion entity, rather than a product company. The transfer from a large operating company (Level 3/Lumen) to a newly formed LLC is a strong indicator.
Known asserter in the chain — Present. Sandpiper CDN, LLC has launched litigation asserting this patent against Alphabet (Google) (2:24-cv-03951), Microsoft (2:25-cv-00664), and Comcast (2:24-cv-00886). RPX Insight, a service tracking NPE litigation, has reported on Sandpiper CDN, LLC's campaigns, indicating it is recognized as an asserter.
Repeat correspondent across the chain — Present. Matthew J. Antonelli of Antonelli Law is listed as the correspondent for the 2024-04-26 assignment to SANDPIPER CDN, LLC (Reel 059941/0457). While no prior correspondents are explicitly listed in the provided snippets for earlier transfers, Matthew J. Antonelli is a known attorney associated with patent assertion entities. His appearance on this crucial transfer to a recognized asserter is a strong signal.
Cascading transfers — Unclear. There are multiple transfers related to SAVVIS and MOUNT SHASTA ACQUISITION LLC around 2007 and 2012. However, without full access to the USPTO assignment records for all related applications and the details of these corporate transactions (mergers, changes of name), it's difficult to definitively categorize them as cascading transfers aimed at assertion rather than corporate restructuring. The most recent transfer in 2024 is a direct transfer from Level 3 to Sandpiper CDN.
Pre-litigation transfer — Present. The assignment to Sandpiper CDN, LLC occurred on March 29, 2024. The first infringement suit by Sandpiper CDN, LLC against Alphabet (Google) (case 2:24-cv-03951) was filed in the Central District of California in 2024. While the exact filing date of the Google suit isn't given for "March 2024", the proximity of the March 29, 2024 assignment to a 2024 filing clearly indicates a pre-litigation transfer. This is further reinforced by the November 2024 filing against Comcast [cite: litigation summary] and 2025 filing against Microsoft [cite: litigation summary].
Bankruptcy fire-sale — Not present. Level 3 Communications LLC was acquired by CenturyLink (now Lumen Technologies). The sale of CDN assets by Level 3 to Sandpiper CDN, LLC in 2023/2024 was a strategic decision to exit the CDN market, not a bankruptcy fire-sale.
Privateering — Unclear. While Level 3/Lumen exited the CDN market, it's not explicitly stated that Sandpiper CDN is asserting the patents on behalf of Lumen. The RPX Insight article states Level 3 "decided to exit the CDN market in 2023 and began selling off its CDN assets. Level 3 sold the Asserted Patents to Plaintiff Sandpiper CDN on March 29, 2024". This is a sale, not necessarily a privateering arrangement, though the line can be blurry.
Defensive aggregator (anti-NPE) — Not present. The patent is currently held by Sandpiper CDN, LLC, which is actively asserting it in litigation.

Verdict

NPE — high confidence

The patent exhibits several strong NPE signals. The transfer from operating company Level 3 Communications, LLC (now part of Lumen Technologies) to a newly formed entity, Sandpiper CDN, LLC, occurred just before the initiation of multiple infringement lawsuits against major technology companies. Sandpiper CDN, LLC is recognized by RPX Insight as an asserter and the correspondent attorney, Matthew J. Antonelli, is associated with patent assertion entities. These factors strongly indicate an NPE assertion strategy.

(USPTO Assignment Center search for US8478903: https://assignmentcenter.uspto.gov/patent/search?patentNumber=8478903)