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Sergio TellezST

Sergio Tellez

Data Analyst | Dashboards in Excel and Power BI

€150/day
Móstoles, ES
3-7 years

Average response time: 1 hour

Freelancer profile translated to English.
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About Sergio

I am a Data Analyst specializing in creating dashboards in Excel and Power BI, cleaning databases, and analyzing business information.

I help companies, freelancers, and small businesses with messy Excel data to transform it into clear, useful, and visual information. I work with sales, expenses, inventory, customers, products, KPIs, and monthly reports.

My approach is practical: first, I understand what the business needs to track, then I organize the database, correct errors, remove duplicates, and prepare easy-to-interpret dashboards.

I can help you with:

Database cleaning and refinement.
Dashboards in Excel and Power BI.
Sales, expenses, and inventory analysis.
KPI creation.
Table organization for reports.
Data preparation for decision-making.

I like to work clearly, orderly, and closely, explaining each delivery so that the client not only receives a file but a tool they can actually use.
  • Spanish

    Native or bilingual

  • English

    Basic

Remote only
Primarily works remotely

Experience

  • Banco Falabella & Scotiabank Colpatria
    Reporting Analyst • · Data & BI
    BANKING AND INSURANCE
    September 2020 - April 2023 (2 years and 7 months)
    Colombia
    Operational and financial analysis of two simultaneous banking projects. Coordination of a team of 5 analysts and responsibility for the complete data cycle (ETL → modeling → dashboard → forecast).
    • • Designed dashboards in Power BI and automated reports with Excel/VBA and Power Query: hourly updates and operational deviation alerts.
    • • Built a budget control panel for €621,000 (8 categories, 3 related tables, DAX measures) that monitored 76.6% execution and detected deviations before closing.
    • • Tracking of +40 KPIs (productivity, conversion, sales) and monthly, quarterly, and semestral forecasts of revenue and indicators.
    • • Administrative support to the financial and operations area: monthly closing, internal order management, document control, and CRM administration (client registration, weekly data cleansing).
    • • Coordinated a team of 5 analysts and applied GDPR/LOPD protocols on sensitive data.
    Achievements
    Microsoft Power BI Advanced Microsoft Excel Data Analysis Business intelligence Reporting
  • Áncora Servicios Integrales S.L. (Operación MRW)
    Operational Analyst
    LOGISTICS AND SUPPLY CHAIN
    August 2024 - April 2025 (8 months)
    Madrid, Spain
    • • Built an interactive dashboard (Excel + pivot tables + macros) for 15,000 deliveries, 50 drivers, 7 zones, and 4 merchants, with a real effectiveness rate of 98.3%.
    • • Designed the custom dataset (15,000 rows × 12 columns), normalized dates and reasons, and validated integrity before loading to the panel.
    • • Identified that 92% of incidents originated from traffic (Madrid accounted for 35% of the volume) → proposed redesign of routes and time slots.
    • • Daily and monthly closing reporting to management: 3,000–5,000 packages/day, 99% accuracy, -20–30% in operational errors.
    • • Administrative support to the base: access management, document control, incident registration, and preparation of tracking reports by fleet and zone.
    Advanced Microsoft Excel Data Analysis Process Automation Reporting Data Cleaning
  • Milo Transporte (Operación Carrefour & IKEA)
    Operations Analyst
    LOGISTICS AND SUPPLY CHAIN
    August 2023 - May 2024 (9 months)
    Madrid, Spain
    • • Cost and profitability analysis per driver: identified deviations, optimized routes, and built monthly expense projections.
    • • Real-time monitoring of delivery KPIs (productivity, service times, route compliance) with reporting to coordination.
    • • Data validation and traceability via PDA and internal systems; liaison with external clients (Carrefour, IKEA).
    Business intelligence delivery notes Advanced Microsoft Excel Data Analysis Logistics

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Education

  • ASIR + Data/BI Portfolio
    2026
    ASIR + Portafolio Data/BI
  • Higher Technician in
    Prometeo by thePower
    2026
    Técnico Superior en

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