Also listed on Return Path, Inc., an earlier holder on the record. The recorded assignments below show how it moved.
Collateral for a security interest recorded Dec 8, 2025 (U.S. Bank Trust Company, National Association).
Term ends May 2, 2033 · High confidence
20-year base term ends Mar 15, 2033
Held by Proofpoint, Inc.
Filed Mar 15, 2013 as application 13/843,383 · Granted Sep 22, 2015
Base term plus 48 days of patent term adjustment (USPTO delay)
Today
2013
2033
Clock starts
Mar 15, 2013
Mar 15, 2013
Term ends
May 2, 2033
May 2, 2033
Granted
Sep 22, 2015
Sep 22, 2015
base term
patent term adjustment
fee events
Updated Nov 14, 2026 · includes USPTO assignment & status data published Nov 14, 2026 and grant & fee data published Nov 10, 2026 (weekly) · how we know
48
Days of term adjustment
Read from the USPTO patent term adjustment record, not recalculated here.
None
Terminal disclaimer
No disclaimer on this record.
2 of 3
Maintenance fees paid
Three maintenance fees fall due, at 3.5, 7.5 and 11.5 years from grant. This counts the ones the record shows paid.
This patent's term runs 48 days past its 20-year base term on prosecution delay. 2 of 3 maintenance fees are paid so far. Confidence: High. from the record
How we calculated this date
One row per rule, each showing its own input and what it did to the date. A step we could not verify says so instead of resolving itself.
| Step | Input | Date after this step | Confidence |
|---|---|---|---|
| Base term, 20 years from filing | Clock starts Mar 15, 2013, when this application, 13/843,383, was filed | Mar 15, 2033 | High confidence |
| Continuity chain | Every parent in the chain resolved | no change | High confidence |
| Patent term adjustment | +48 days, USPTO patent term adjustment record | May 2, 2033 | High confidence |
| Terminal disclaimer cap | None on record | no cap applied | High confidence |
| Patent term extension | None on file | no change | High confidence |
| Fee events | 2 of 3 maintenance fees paid | In force | High confidence |
| Computed term end | The steps above, in order | May 2, 2033 | High confidence |
Assignments
Assignment documents as recorded at the USPTO, oldest first, with the reel and frame each was recorded at. A recorded assignment is a filed document, not a statement of current ownership, and the absence of a later one is not evidence that the last one still stands.
| Recorded | Assignor | Assignee | Conveyance |
|---|---|---|---|
| May 17, 2013 Reel 30463, frame 140 | Dreller, Bryan P.; Colburn, Gregory J.; Bilbrey, George M. | Return Path, Inc. | Assignment of Assignor's Interest |
| Jun 22, 2015 Reel 35997, frame 654 | Return Path, Inc. | Silicon Valley Bank | Security Agreement |
| Aug 26, 2016 Reel 39552, frame 445 | Silicon Valley Bank | Return Path, Inc. | Release of Security Interest |
| Sep 1, 2016 Reel 39618, frame 1 | Return Path, Inc. | Proofpoint, Inc. | Assignment of Assignor's Interest |
| Aug 31, 2021 Reel 57389, frame 615 | Proofpoint, Inc. | Goldman Sachs Bank USA, as Collateral Agent | First Lien Intellectual Property Security Agreement |
| Aug 31, 2021 Reel 57389, frame 642 | Proofpoint, Inc. | Goldman Sachs Bank USA, as Collateral Agent | Second Lien Intellectual Property Security Agreement |
| Mar 21, 2024 Reel 66865, frame 648 | Goldman Sachs Bank USA, as Agent | Proofpoint, Inc. | Release of Second Lien Security Interest in Intellectual Property |
| Dec 8, 2025 Reel 73889, frame 677 | Proofpoint, Inc. | U.S. Bank Trust Company, National Association, as Collateral Agent | Second Lien Intellectual Property Security Agreement |
Sources
Google Patents · The patent document at USPTO · Assignment records at USPTO
USPTO account required: This application in Patent Center · USPTO's maintenance fee lookup
Maintenance fee events come from USPTO's own fee records. Its fee lookup asks for the patent number and the application number.
What's changing
May 2033
Term ends May 2, 2033. Maintenance fees still fall due before then
Note
The 48 days of patent term adjustment (USPTO delay) are read from the USPTO record, not recalculated by us
Citations
135
later US patents cite this one
That is top 5% of utility patents granted in 2015 in our data, the only group it is compared against.
How we rank
Every date shows its work: the base term, any term adjustment or extension, any disclaimer cap, and the maintenance fee record, each with a confidence tier. How this record was built
Computed patent terms end on the dates shown. Related patents and pending applications may cover overlapping subject matter.
In force means the term is running and no lapse is on record. It is not a finding that the patent is valid.