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Search›Companies›O3 Energy OÜ
14291372ActivePrivate limited company

O3 Energy OÜ

Harju maakond, Tallinn, Kristiine linnaosa, Vesipapi tn 2·EMTAK 71121 — Constructional engineering-technical designing and consulting·8+ years
Andmed · ···
On this page
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Overview

e-Business Register · 18 h ago
Registry code
e-Business Register
Legal form
Private limited company
Registered
07.07.2017e-Business Register
Address
Vesipapi tn 2, Kristiine linnaosa, Tallinn, 10619 Harju maakondADS · e-Business Register
E-mail address
info@o3.eee-Business Register
Website
www.o3.eee-Business Register · domain active
Telephone
+372 53870338· Telia Eesti ASe-Business Register · TTJA NBA
Principal activity
EMTAK 71121 - Constructional engineering-technical designing and consultinge-Business Register · ETCB
Share capital
3000,00 €e-Business Register
Estonia's public business register
HomeViewsIndustriesBlogSourcesAbout

Public registry of Estonian companies — every fact traceable to a source and a date. Free and ad-free for everyone.

Nimistu MTÜ
Address: Parda tn 8, 10151 Tallinn, Estonia
E-mail: info@nimistu.ee

Browse

  • Home
  • Views
  • Industries
  • Recent registrations

Data

  • 72 sources
  • Database
  • Extensions
  • MCP

Organisation

  • About
  • For journalists
  • Donation terms
  • Refunds
  • Terms
  • Privacy
  • Contact
© 2026 Nimistu MTÜ. License CC-BY-SA 4.0 · details
Revenue 2025 (I kv)
0 €
▼ 100% vs 2024 I kv
As of 10.04.2026 (MTA)
Employees
–
2025 (MTA)
Taxes paid
0 €
State + labour taxes · 2025 (I kv)
Tax debt
0 €
As of 26.06.2026 (MTA)

Registered 7. juuli 2017, primary activity: Constructional engineering-technical designing and consulting. Main place of business in Kristiine linnaosa, Tallinn, Harju maakond.

Data · 10 sourcese-Business Register · 5 min agoMTAMTRBuiltWithWeb tech scan
e-Business Register ↗
Revenue 2025 (I kv)
0 €
▼ 100% vs 2024 I kv
As of 10.04.2026 (MTA)
Employees
–
2025 (MTA)
Taxes paid
0 €
State + labour taxes · 2025 (I kv)
Tax debt
€0
As of 26.06.2026 (MTA)

Officers (2)

e-Business Register · 18 h ago
MV
Mats Viisileht
Born 1990 · 36 y · board member since 05.05.2025
Board member
MH
Mihkel Hiielaid
Born 1993 · 32 y · board member since 05.05.2025
Board member

Founders

e-Business Register · 18 h ago
OT
O3 Technology OÜLEGAL PERSON
Legal person · 14062364 · founder since 07.07.2017
Founder · 3k €

Shareholders

e-Business Register · 18 h ago
OT
O3 Technology OÜLEGAL PERSON
Legal person · 14062364 · shareholder since 02.09.2023
Shareholder 100% · 3k €

Beneficial owners (2)

e-Business Register · 18 h ago
MK
Martin Kiil
Born 1989 · 37 y · ultimate beneficial owner since 22.10.2018
Ultimate beneficial owner
MT
Mikk Tasa
Born 1987 · 39 y · ultimate beneficial owner since 22.10.2018
Ultimate beneficial owner

Annual reports (6)

e-Business Register · annual reports · 6 päeva tagasi
Revenue 2024
5k €
↘ -94.8% vs 2023
State taxes 2023
52k €
↗ +5.7% vs 2022
Employees 2024
1
↘ -75.0% vs 2023
YearRevenueProfit

Taxes, revenue and employees

Estonian Tax and Customs Board · 10.04.2026 as of
50k €25k €0

Licences (1)

MTR · 17 h tagasi
Active licences
1
Other1
Oldest · Newest
2017→2017
Oldest licenceEEP003902 · 17.07.2017
Active1 / 1
EEP003902
Projekteerimine
Majandustegevusteade
From17.07.2017
UntilOpen-ended
Valid

Tech stack

Website analysis · 4 päeva tagasi
Domains (1)
www.o3.ee
SRCÄriregister
Mobile carrier
+372 53870338Telia Eesti AS

History

last 2 years · MTA + ÄR + MTR + Procurements
2025
30.06.2025ReportEsitati 2024. aasta aruanne— Käive 4539 €
05.05.2025OfficerAstus juhatusse2×expand ›hide ⌃
  • Mihkel Hiielaid
  • Mats Viisileht
05.05.2025FilingMuutmiskanne2×expand ›

Connected companies

Same-person ties · e-Business Register

O3 Energy OÜ is connected to 10 other companies through 4 people who hold a role here and elsewhere. The strongest tie runs through Mats Viisileht (3 companies).

Total connections
10
via 4 people
Connecting people
4
Active here
Distinct roles
2
Board member · Ultimate beneficial owner
Strongest tie
Mats
3 companies
Via personMats Viisileht
Equity
Assets
Employees
20244539 €−8130 €2k €2k €130.06.2025
202387 276 €−4991 €11k €25k €416.04.2024
202292 614 €1034 €16k €29k €429.06.2023
202166 601 €−2191 €14k €28k €305.05.2022
202071 686 €11 554 €17k €27k €311.06.2021
201972 770 €−6010 €5k €16k €417.04.2020
Original files in PDF – the full register on e-Business Register.View reports on e-Business Register
2022202320242025
YearRevenue (a)State taxesTaxes on workforceEmployees (Q4)
2025I Q0 €0 €0 €–
202413 557 €10 994 €8879 €–
202386 570 €52 493 €38 086 €2
202291 694 €49 644 €34 670 €5
Quarterly breakdown
YearQ1Q2Q3Q4
Revenue 20250 €–––
State taxes 20250 €–––
Taxes on workforce 20250 €–––
Employees 2025––––
Revenue 202414k €0 €0 €0 €
State taxes 202411k €–––
Taxes on workforce 20249k €–––
Employees 2024––––
Revenue 202322k €14k €25k €25k €
State taxes 202313k €11k €14k €15k €
Taxes on workforce 20239k €9k €10k €10k €
Employees 20234332
Revenue 202222k €34k €12k €24k €
State taxes 202211k €19k €10k €11k €
Taxes on workforce 20227k €13k €8k €6k €
Employees 20225555
hide ⌃
  • Ä 50060811 / 8 · Olek: Jõustunud
  • Kanne nr 8 · kanne
3
Mihkel Hiielaid3
Martin Kiil2
Mikk Tasa2
MV
Mats Viisileht
board member
3 other companies›
CompanyRoleReg. code
MAVI OÜ
Board memberFounderUltimate beneficial ownerShareholder 100%
16925384
O3 Inseneribüroo OÜ
Board memberUltimate beneficial owner
12321790
O3 Technology OÜ
Board member
14062364
MH
Mihkel Hiielaid
board member
3 other companies›
CompanyRoleReg. code
Hiimek OÜ
FounderUltimate beneficial ownerShareholder 100%Board member
16232043
O3 Inseneribüroo OÜ
Board member
MK
Martin Kiil
ultimate beneficial owner
2 other companies›
CompanyRoleReg. code
Hooneühistu Jahu 8a
Board member
80075800
O3 Technology OÜ
FounderUltimate beneficial ownerShareholder 25%
MT
Mikk Tasa
ultimate beneficial owner
2 other companies›
CompanyRoleReg. code
O3 Inseneribüroo OÜ
Founder
12321790
O3 Technology OÜ
FounderUltimate beneficial ownerShareholder 25%
Ultimate beneficial owner
12321790
O3 Technology OÜ
Board member
14062364
14062364
14062364