EM Microelectronic — 70 prefixes (MA-L); ultra-low-power BLE / RFID / NFC silicon, OUI ≠ device brand (Swatch Group)

EM Microelectronic holds 70 MA-L blocks, all registered to "EM Microelectronic" at Rue des Sors 3, Marin-Epagnier, Neuchatel CH 2074 — the identical registry address on every one of the 70 entries. EM is a Swiss fabless-and-fab semiconductor maker founded in 1975 and wholly owned by The Swatch Group since 1985; it designs ultra-low-power integrated circuits rather than finished consumer devices, so these OUIs surface on third-party OEM products that embed EM silicon. The dominant MAC-bearing families are EM's Bluetooth Low Energy SoCs — the EM9304 (Bluetooth 4.2, marketed as one of the smallest BLE SoCs at its 2016 launch) and the EM9305 / em|bleu (Bluetooth 5.4) — which end up in fitness wearables, healthcare monitors, smart-home sensors, and IoT nodes. EM also ships LF/HF/UHF RFID and NFC ICs (em|echo, em|echo-V, em|aura-sense), smart-card ICs, CoolRISC microcontrollers, real-time clocks, LCD drivers, and power-management parts. The analyst takeaway is the chipset pattern: an EM Microelectronic OUI most often identifies a BLE or RFID/NFC product built on EM silicon, and the consumer brand on the box is usually unrelated to "EM." No EM-specific CVEs were found in open sources; EM's BLE SoCs carry the standard BLE attack surface (passive sniffing, pairing MITM, relay on unencrypted links), and while some legacy LF RFID parts (EM4100-compatible) are a well-known clonable technology, EM also sells higher-security ISO/IEC 15693 variants marketed for anti-counterfeiting. The IEEE registry publishes no assignment dates, so none is stated here.

IEEE assignment

70 prefixes → "EM Microelectronic", all at Rue des Sors 3, Marin-Epagnier, Neuchatel CH 2074 [Confirmed] — IEEE MA-L (enrichment/registries/oui.csv)

Registry / block size

MA-L (24-bit OUI); 70 blocks in the cached IEEE registry. No MA-M or MA-S assignments exist (0 rows in mam.csv / oui36.csv) [Confirmed] — enrichment/registries/oui.csv, mam.csv, oui36.csv. NOTE: third-party trackers report a moving count (maclookup.app ≈70 mid-2026; hwaddress.com lists 60+) as IEEE publishes new blocks; the 70 here is the cached-registry ground truth.

HQ / country

Rue des Sors 3, Marin-Epagnier, Neuchâtel 2074, Switzerland (CH) [Confirmed] — IEEE MA-L; https://hwaddress.com/company/em-microelectronic/

Company status

active; founded 1975, wholly owned by The Swatch Group since 1985 (operating as "EM Microelectronic – Marin SA") [Confirmed] — https://en.wikipedia.org/wiki/EM_Microelectronic ; https://www.swatchgroup.com/en/companies-brands/electronic-systems/em-microelectronic

Device types

not a device brand — fabless/fab IC maker. EM silicon appears in finished OEM products: BLE SoCs (EM9304 / EM9305 'em|bleu') in fitness wearables, healthcare monitors, smart-home sensors, IoT nodes; LF/HF/UHF RFID and NFC ICs in retail/supply-chain tags, access-control and animal-ID, anti-counterfeiting labels; smart-card ICs; CoolRISC ultra-low-power MCUs; real-time clocks, LCD drivers, power-management and sensor ICs [Confirmed] — https://en.wikipedia.org/wiki/EM_Microelectronic ; https://wiot-group.com/think/en/news/em-microelectronic-introduces-the-embleu-ic/

Notable products

EM9304 (BLE 4.2 SoC, 2016); EM9305 / em|bleu (BLE 5.4 SoC, mass production 2024–2025); em|echo (UHF+HF RFID combo, 2015); em|echo-V (NFC + RAIN RFID single chip, 2020); em|aura-sense (battery-less IoT RFID sensor platform); EM4325 (BAP RFID with integrated temperature sensor); EM4126 (HF RFID for high-value items) [Confirmed] — https://en.wikipedia.org/wiki/EM_Microelectronic ; https://www.swatchgroup.com/en/swatch-group/innovation-powerhouse/internet-things/new-emecho-v-nfc-rain-rfid-single-chip

Fabrication / provenance

operates its own semiconductor fabrication and display facilities in Switzerland and also uses external foundries; design centers in Colorado Springs (USA) and Prague (Czech Republic) [Likely] — https://en.wikipedia.org/wiki/EM_Microelectronic (single-source; not independently corroborated)

Security context

no EM-specific CVEs or named advisories found in open sources. BLE SoCs (em|bleu / EM9304 / EM9305) carry the standard BLE attack surface (passive sniffing, pairing MITM, relay on unencrypted links) — a host-stack/configuration concern, not a chipset-specific flaw. Some legacy LF RFID parts (EM4100-compatible) are well-documented as clonable; EM also sells higher-security ISO/IEC 15693 variants marketed for anti-counterfeiting [Likely] — https://en.wikipedia.org/wiki/EM_Microelectronic ; https://www.electronicspecifier.com/companies/em-microelectronic

Verified sample prefixes (all MA-L, EM Microelectronic)

50:F2:22, 44:D5:C1, 68:53:9D, 80:65:59 [Confirmed] — IEEE MA-L (enrichment/registries/oui.csv)

Special note

Chipset-OUI flag (70 MA-L blocks). An EM OUI most often identifies a BLE or RFID/NFC product built on EM silicon, regardless of the brand on the box. Swatch Group parentage = Swiss provenance. The IEEE registry publishes no assignment dates, so none is stated here; third-party "date registered" values (database artifacts ranging 2011–2026) must not be presented as IEEE facts. [Confirmed]

Related vendors

The Swatch Group (parent); peer ultra-low-power / BLE & RFID silicon makers — not registrant-linked

Analyst note

Treat an EM Microelectronic OUI as "device using EM silicon," not a specific consumer brand — typically a BLE wearable/sensor or an RFID/NFC product; the brand on the box is usually unrelated to "EM."