Open to opportunities

Sebastián Castellanos

@sebastincastellanos

Message

Billing & client relations professional streamlining corporate banking workflows and reporting for faster cycle times.

Guatemala

Message

What I'm looking for

I’m looking for a role where I can own client portfolio support and billing workflows, strengthen KYC/AML and reporting accuracy, and keep improving time-to-market through automation and better operational routing.

I handle 170+ corporate client portfolios at Citibank NA Sucursal Guatemala, supporting international transactions and daily banking operations while maintaining a 90% “Very Satisfied” rating. I lead onboarding and KYC/AML compliance with Relationship Managers, coordinate cross-functional product rollouts, and route operational emails into Jira using an automated workflow integrated with Gemini.

Before that, I built automated reporting at Conduent Business Services Guatemala—delivering revenue, expense, and CM reports for 16+ accounts and running monthly reconciliations under US GAAP. Earlier roles included automating billing with a dynamic database to cut cycle prep from 3 months to 1 week, and creating Excel-based tools at Tigo Guatemala to reduce service response time from 3+ hours to minutes.

Experience

Work history, roles, and key accomplishments

Current

Billing and Relationship Support Associate

Current

Citibank NA Sucursal Guatemala

Jul 2022 - Present (4 years 1 month)

Owned 170+ corporate client portfolio with 90% Very Satisfied rating; led onboarding and KYC/AML compliance, and implemented automated workflow routing operational emails into Jira.

KYC AML Jira Gemini Cross functional Coordination Client Relationship Management

Accounting Analyst II

Conduent Business Services

Jun 2021 - Jul 2022 (1 year 1 month)

Delivered revenue, expense, and CM reports for 16+ accounts worth $54M+ annually; prepared monthly reconciliations under US GAAP and partnered on cost analysis.

Financial Reporting US GAAP Cost Analysis Hyperion Essbase

Reporting Analyst

Conduent Business Services

Oct 2019 - May 2021 (1 year 7 months)

Automated billing process via dynamic database, cutting cycle from 3 months to 1 week; built collection plan reducing AR reserves and improving revenue recognition.

Billing Automation Database Management AR

Account Executive

Guatemalan Construction Chamber

Jan 2019 - Sep 2019 (8 months)

Prospected and onboarded corporate members, exceeding monthly sales targets by 15% in the first 6 months.

Sales Prospecting Client Onboarding

Customer Success & Account Management

Tigo Guatemala

Sep 2010 - Mar 2018 (7 years 6 months)

Promoted from Representative to Store Manager to Account Management, managing 150+ B2B/government clients; built Excel-based tools improving efficiency and reducing service response time.

Account Management B2B Sales Staff Scheduling