What's causing the sudden increase in failed card transactions for Monzo Business accounts?

Introduction

The sudden increase in failed card transactions for Monzo Business accounts is a critical issue that demands immediate attention. This problem directly impacts our core service offering and could have severe consequences for customer satisfaction, revenue, and brand reputation. I'll approach this analysis systematically, focusing on identifying the root cause, validating hypotheses, and developing both short-term fixes and long-term solutions.

Step 1

Clarifying Questions (3 minutes)

• Looking at the timing, I'm thinking this might be a recent development. When exactly did we start noticing this increase in failed transactions?

Why it matters: Pinpointing the timeframe helps us correlate the issue with potential changes or events. Expected answer: Within the last week or two. Impact on approach: A sudden spike would suggest a specific trigger, while a gradual increase might indicate a systemic issue.

• Considering the scope, I'm wondering if this affects all Monzo Business accounts or a specific subset. Are we seeing this issue across all business account types or transaction volumes?

Why it matters: This helps us determine if it's a universal problem or limited to certain account characteristics. Expected answer: It's affecting all business accounts, but more pronounced in high-volume accounts. Impact on approach: If it's specific to certain accounts, we'd focus on unique features or usage patterns of those accounts.

• Given the nature of the problem, I'm curious about the error messages or reasons provided for these failed transactions. What specific error codes or messages are we seeing?

Why it matters: Error messages can provide crucial clues about the underlying cause. Expected answer: A mix of "Insufficient funds" and "Transaction declined by issuer" errors. Impact on approach: Different error types would lead us to investigate different parts of the transaction process.

• Thinking about recent changes, have we implemented any updates to our payment processing systems or partnerships in the last month?

Why it matters: Recent changes are often correlated with new issues. Expected answer: A minor update to the fraud detection algorithm was rolled out two weeks ago. Impact on approach: This would shift our focus to the potential impact of that specific update.

• Considering external factors, have we noticed any unusual patterns in transaction attempts, such as increased volume or changes in transaction types?

Why it matters: External factors could be straining our systems or triggering new behaviors. Expected answer: There's been a 20% increase in international transactions over the past month. Impact on approach: This would lead us to investigate our international transaction handling and potential capacity issues.