How many employees work at O'Halloran & O'Brien?
O'Halloran & O'Brien Ltd. has approximately 506 total employees worldwide as of March 2026, according to Revelio Labs workforce intelligence data. O'Halloran & O'Brien’s total headcount has declined 10.0% from 563 employees in 2023 to 506 in 2026.
Is O'Halloran & O'Brien hiring right now?
Yes, O'Halloran & O'Brien is actively hiring. O'Halloran & O'Brien had 5 active job postings in 2026, a 50.0% increase from 2025 — see job openings & hiring trends.
About O'Halloran & O'Brien’s Workforce
O'Halloran & O'Brien Ltd. is an Engineering and Construction Services company that employs 506 people worldwide as of March 2026. It is the 11th-largest by headcount among its peers. Founded in 1972, the company is headquartered in London, United Kingdom.
O'Halloran & O'Brien's workforce has declined 10.0% from 2023 to 2026, down 3.5% year over year in 2026. It fell to a low of 506 in 2026 Q1 before recovering. Its workforce is concentrated most in Northern Europe (96.9%), followed by Eastern Europe (1.4%) and Sub-Saharan Africa (0.9%).
O'Halloran & O'Brien's functional groups are Finance and Operations (52.4%), Engineering (25.2%), and Sales and Marketing (22.3%). The average salary is $65,201, highest in Northern Europe at a median of $60,000, up 0.5% year over year in 2026.
O'Halloran & O'Brien's active job postings rose 50.0% in 2026 to 5, with new postings per month climbing from 5 in 2023 to 23 in 2026. Overall employee sentiment is neutral but improving.
Sourced from Revelio Labs workforce data.
- Headquarters
- London, United Kingdom
- Founded
- 1972
- Industry
- Engineering and Construction Services
- Employees
- 506
- YoY
- -3.5% (-58)
As of March 2026
O'Halloran & O'Brien workforce metrics
Unlock hiring rate, attrition rate, and 12 additional workforce metrics for O'Halloran & O'Brien. Compare to peers, export the dataset, and access the full quarterly history.
Unlock MetricsO'Halloran & O'Brien Annual Employee Count (2023-2026)
- O'Halloran & O'Brien had 506 employees in 2026, a 3.5% decline (-58) from 2025.
- O'Halloran & O'Brien had 508 employees in 2025, a 4.4% decline (-106) from 2024.
- O'Halloran & O'Brien had 614 employees in 2024, a 1.5% decline (+21) from 2023.
- O'Halloran & O'Brien had 593 employees in 2023, a 1.9% decline (+32) from 2022.
O'Halloran & O'Brien's total workforce has declined from 563 employees in 2023 to 506 in 2026. O'Halloran & O'Brien's headcount peaked at 630 in 2024.
O'Halloran & O'Brien Ltd. quarterly employee count
| Year | Qtr | Employees | YoY Change | YoY % |
|---|---|---|---|---|
| 2026 | Q1 | 506 | -58 | -3.5% |
| 2025 | Q4 | 508 | -106 | -4.4% |
| 2025 | Q3 | 512 | -118 | -5.8% |
| 2025 | Q2 | 524 | -95 | -6.1% |
| 2025 | Q1 | 564 | -47 | -3.1% |
| 2024 | Q4 | 614 | +21 | -1.5% |
| 2024 | Q3 | 630 | +63 | +0.2% |
| 2024 | Q2 | 619 | +56 | +1.2% |
| 2024 | Q1 | 611 | +66 | +1.3% |
| 2023 | Q4 | 593 | +32 | -1.9% |
| 2023 | Q3 | 567 | -3 | -2.9% |
| 2023 | Q2 | 563 | -7 | -1.1% |
See O'Halloran & O'Brien's complete headcount history, including quarterly breakdowns.
Get the DataO'Halloran & O'Brien Employee Count by Region (2026)
Northern Europe accounts for the largest share of O'Halloran & O'Brien's global workforce with approximately 97% of total employees, followed by Eastern Europe and Sub-Saharan Africa.
O'Halloran & O'Brien employees by region
| Region | Employees | % of Total |
|---|---|---|
| Northern Europe | 490 | 96.9% |
| Eastern Europe | 7 | 1.4% |
| Sub-Saharan Africa | 4 | 0.9% |
| Western Europe | 3 | 0.6% |
| Pacific Islands | 1 | 0.2% |
Drill into city-level data, hiring trends by region, and historic geographic shifts.
Unlock Geographic DataO'Halloran & O'Brien Employee Count by Department (2026)
O'Halloran & O'Brien's employee groups are Finance and Operations (52.4%), Engineering (25.2%), and Sales and Marketing (22.3%).
O'Halloran & O'Brien employees by department
| Department | Employees | % of Total |
|---|---|---|
| Finance and Operations | 259 | 52.4% |
| Engineering | 125 | 25.2% |
| Sales and Marketing | 110 | 22.3% |
Compare O'Halloran & O'Brien's department mix to industry peers.
See Full DataO'Halloran & O'Brien Employee Salary by Region (2026)
O'Halloran & O'Brien's average employee salary is $65,201 globally. Employees in Northern Europe receive the highest compensation.
O'Halloran & O'Brien median employee salary by region (USD)
| Region | Median Salary |
|---|---|
| Northern Europe | $60,000 |
Unlock salary by role, level, and city — and compare to O'Halloran & O'Brien's industry peers.
Unlock Salary DataO'Halloran & O'Brien Job Openings and Hiring Trends (2023-2026)
- O'Halloran & O'Brien had 5 active job postings in 2026, a 50.0% increase (-2) from 2025.
- O'Halloran & O'Brien had 7 active job postings in 2025, a 35.3% decline (-3) from 2024.
- O'Halloran & O'Brien had 10 active job postings in 2024, a 75.0% decline (-12) from 2023.
- O'Halloran & O'Brien had 22 active job postings in 2023, a 166.7% increase from 2022.
- Hiring velocity in 2026: 23 new roles/month, up from 17 in 2025 and 28 in 2024.
O'Halloran & O'Brien's hiring is accelerating: active job postings rose 50.0% in 2026 to 5, with new postings per month climbing from 5 in 2023 to 23 in 2026.
Track new postings per month, role-level demand, and hiring velocity vs. peers.
Unlock Hiring DataO'Halloran & O'Brien Employee Sentiment (2026)
Revelio Labs tracks employee sentiment across O'Halloran & O'Brien's workforce based on public professional data. Overall sentiment is neutral and has improved year over year in 2026.
Overall
Unlock the full sentiment breakdown by department, tenure, and trend over time.
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Frequently Asked Questions About O'Halloran & O'Brien
- How fast is O'Halloran & O'Brien growing?
- In 2026, O'Halloran & O'Brien's headcount shrank 3.5% to 506 employees, down from 564 in 2025.
- See the full headcount history
- Where are O'Halloran & O'Brien employees located?
- Most O'Halloran & O'Brien employees are based in Northern Europe (96.9% of headcount), followed by Eastern Europe and Sub-Saharan Africa.
- Explore where the workforce is based
- What is the average salary at O'Halloran & O'Brien?
- The average employee salary at O'Halloran & O'Brien is approximately $65.2k per year.
- Analyze the salary distribution
- How many new job postings does O'Halloran & O'Brien open per year?
- In Q1 2026, O'Halloran & O'Brien opened 69 new job postings. In 2025, O'Halloran & O'Brien opened 199 new job postings — about 17 per month.
- Track hiring trends by role
- When was O'Halloran & O'Brien founded and where is it headquartered?
- O'Halloran & O'Brien was founded in 1972 and is headquartered in London, United Kingdom.
- Compare O'Halloran & O'Brien to industry peers
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