Chartered Accountant · New York
Wai Yin Choi
Finance systems, controls, and a workbench of things I’m making.
01 / Workbench
Workbench.
Work in progress, on purpose.
Also on the bench
Public repos, synced at build time.
02 / Experience
Experience.
The work so far.
Wai Yin Choi
New York · hello@wychoi.com · linkedin.com/in/awychoi · github.com/awychoi
UNICEF Finance Specialist → Budget Specialist Finance systems, budgets, and controls across UNICEF’s global operations.
2021 — Present
Budget Specialist
- Lead cross-functional budget and position work across accounting, grants management, IT, and HR.
- Build Power BI dashboards and maintain the Python standard-cost model; develop the policy and SOPs around both.
- Development-team member for UNICEF’s SAP Fiori budget formulation tool, replacing a long-standing legacy planning database.
- Guide field offices on annual, ad-hoc, and multi-year budgeting; review submissions before ERP implementation.
2015 — 2021
Finance Specialist
- Managed HACT transaction support and the eZHACT tool; worked with IT on automated controls that reduced manual checks and support requests.
- Drafted and reviewed accounting policies and procedures across Finance and IT, aligning them with IPSAS and internal control requirements.
- Led monthly SAP closures and year-end reconciliation with country offices; trained country and regional teams.
- Helped shape UNICEF’s Global Shared Services Centre, defining SOPs, core deliverables, and cost-recovery inputs.
Secondment · 2020
Grants Specialist, Donor Management Unit
- Recorded donor conditionality, cleared donor receivables, and managed US-funded reimbursement claims.
- Built Power BI dashboards for fund-flow monitoring and supported the team’s shift from transactional work to oversight.
Auditor General of South Africa Auditor → Audit Manager Public-sector audit from trainee to manager, including a secondment to the United Nations Board of Auditors in New York.
2010 — 2015
Audit Manager
- Managed a portfolio of government audit engagements and led audit teams.
- Assessed financial reporting and controls against IFRS and GAAP; presented findings to executives, accounting officers, and audit committees.
- Authored management and final audit reports; mentored and coached team members.
Secondment · New York · 2009 — 2010
Assistant Audit Manager, UN Board of Auditors
- Represented South Africa on the United Nations Board of Auditors, auditing UN entities including peacekeeping operations, UNDP, UNFPA, and UNJSPF.
- Applied UNSAS and IPSAS; worked with international audit teams and assessed management judgment against UN Financial Regulations and Rules.
- Conducted field audits in high-risk environments while maintaining audit quality and professional skepticism.
2006 — 2010
Assistant Audit Manager / Auditor
- Led small and medium engagement teams on government entities and agreed-upon procedures.
- Built risk-based audit programmes, reviewed working papers, and mentored junior auditors against IRBA quality requirements.
Toolkit
The things behind the record.
Programming & data
- Python
- SQL
- Power Query / ETL
- Power BI
- Excel / VBA
Financial systems
- SAP / ERP
- SAP Fiori
- HACT
- Budget formulation
Accounting & compliance
- IPSAS
- IFRS
- GAAP
- UN Financial Regulations & Rules
AI & automation
- Local LLMs
- Agentic workflows
- Claude Code
- DeepSeek Harness
- Hermes Agent
Languages English · Mandarin · Cantonese
03 / Hello
Hello.
Audit, international finance, and a growing workbench.
Welcome to my space! For years I've had more ideas than time to build them. Agentic AI closed the gap. But just as quickly as I realized how capable they are, I found the limit: focus. Trained on everything, they go off track easily.
The advantage isn't access to AI any more. It's having a bird's eye view, anticipating the pitfalls, spotting the gaps while it's still working, and straightening it out when it drifts. Most of all, it's review by interview: questioning the agent on what it understood, what it assumed, how it got there, and what it left out — and then challenging the answers.
I'm a chartered accountant by trade: twenty-plus years of audit and financial systems. That's where review by interview comes from — and it's the part of the job that transfers best.
04 / Contact
Get in touch.
Email is best. No form, no newsletter, no list.