Fitbit, Inc. — 5 prefixes (MA-L)

A MAC address beginning with F0:51:EA, 58:A8:7B, C8:B6:FE, 5C:75:AF, or 18:00:DB belongs to Fitbit, Inc., typically seen on wireless fitness trackers and smartwatches that sync activity, heart-rate, and sleep data to a companion smartphone app.

Fitbit holds five separate IEEE MA-L (24-bit OUI) blocks — four registered to "Fitbit, Inc." at 199 Fremont Street, 14th Fl, San Francisco, CA, and one ("Fitbit Inc.") to an earlier address, 150 Spear St Ste 200, also San Francisco. The multiple assignments, plus an identifiable, well-documented consumer product line, rule out a bare shell registration.

Google (Alphabet) acquired Fitbit in an all-cash deal that closed January 14, 2021, and Fitbit's hardware and software have since been folded into Google's ecosystem. Devices connect over Bluetooth Low Energy (BLE) to a phone app, with some newer models adding Wi-Fi; an independent MAC-prefix aggregator classifies all five blocks as Device/IoT wearables.

Independent academic and press research found that Fitbit devices historically used static, non-randomized BLE MAC addresses, letting a passive observer correlate a device — and its owner — over time; some models also leaked identifying tokens in BLE advertising payloads even after address randomization was introduced elsewhere in the stack. OUI-based identification reliably flags Fitbit hardware, but is not a guarantee of long-term address uniqueness.

IEEE assignment

5 MA-L prefixes → "Fitbit, Inc." (4 blocks) and "Fitbit Inc." (1 block), same company [Confirmed] — IEEE MA-L

Registry / block size

MA-L (24-bit OUI); 5 IEEE prefixes assigned to this vendor [Confirmed] — the IEEE MA-L registry

Registered addresses

199 Fremont Street, 14th Fl, San Francisco, CA 94105, US (F0:51:EA, 58:A8:7B, C8:B6:FE, 5C:75:AF); 150 Spear St Ste 200, San Francisco, CA 94105, US — earlier address, same company (18:00:DB) [Confirmed] — IEEE MA-L

Company status

acquired by Google (Alphabet), deal closed January 14, 2021; hardware/software progressively absorbed into Google's ecosystem [Confirmed acquisition / Likely current operating detail] — blog.google, cnbc.com

Device types

fitness/activity trackers, smartwatches; BLE sync to companion smartphone app, some newer models add Wi-Fi [Confirmed] — netify.ai

Verified sample prefixes (all MA-L, Fitbit)

F0:51:EA, 58:A8:7B, C8:B6:FE, 5C:75:AF, 18:00:DB [Confirmed] — the IEEE MA-L registry, cross-corroborated by netify.ai

MA-M / OUI-36 assignments

none found under Fitbit in either registry [Confirmed] — the IEEE MA-L registry (the IEEE MA-M registry, the IEEE MA-S registry)

Registration date

not published by IEEE for any of the 5 blocks; third-party "date registered" values elsewhere are database-scrape artifacts, not IEEE facts [Unknown / Confirmed absence of an IEEE date field] — the IEEE MA-L registry

Security note

independent research (MIT 6.857 course paper, a BLE MITM paper, Boston University research covered by BU/Engadget) documents historically static, non-randomized BLE MAC addresses on Fitbit devices enabling passive long-term tracking, and identifying tokens leaking via BLE advertising payloads

[Confirmed] — bu.edu, engadget.com, pmc.ncbi.nlm.nih.gov, courses.csail.mit.edu

Industry recognition

Fitbit is cited by IEEE Spectrum as a notable consumer-electronics product line [Confirmed] — spectrum.ieee.org

Related vendors

Google / Alphabet (parent company since January 2021)

Analyst note

Fitbit's 5 OUI blocks reliably identify genuine Fitbit hardware for asset/device classification; the historically static-BLE-MAC behavior documented in independent research is a privacy/tracking concern for end users, not a reason to distrust the OUI-to-vendor mapping itself.