Capital One·Data Scientist·Technical Phone Screen·Intermediate

Intermediate

Jun 2026

Summary

Capital One data scientist interview with a straightforward portfolio math question. Nothing fancy, just unit conversion and arithmetic, but it's the kind of thing that trips you up if you're not careful about monthly vs annual figures.

Questions Asked (1)

A credit card portfolio has 500,000 active customers. Each card earns an $79 annual fee, $2 in other yearly revenue, and $15 in monthly interest revenue, but costs $5 per month in fraud prevention. What is the total annual profit across the portfolio?

Product Analytics & MetricsPricing & Monetization

Author's notes

The math itself isn't hard but I fumbled for a second because I started adding monthly and annual numbers together without converting first.

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AI HintsAI Generated

Suggested Approach

Break down the problem into annual revenue and cost components per customer, then multiply by the number of customers to get total portfolio profit. Clearly state assumptions about interest revenue and fraud prevention costs being constant across all customers and months.

Pro tip: After calculating the total, sanity-check the result by estimating per-customer annual profit and comparing it to typical credit card profitability metrics. This demonstrates business acumen and catches calculation errors.

1. Identify per-customer annual revenue streams

Calculate the annual fee, other yearly revenue, and annual interest revenue per customer. Note that interest revenue is given monthly, so multiply by 12.

2. Identify per-customer annual costs

Calculate the annual fraud prevention cost per customer by multiplying the monthly cost by 12.

3. Compute per-customer annual profit

Subtract total annual costs from total annual revenue to get the annual profit per customer.

4. Scale to portfolio level

Multiply the per-customer annual profit by the total number of active customers (500,000) to get the total annual profit across the portfolio.

5. Validate and contextualize

Check the reasonableness of the result and mention any assumptions or potential variations (e.g., customer churn, varying interest revenue).

Key Points to Mention

Annual fee revenue: $79 per customer
Other yearly revenue: $2 per customer
Monthly interest revenue: $15, so annual interest revenue = $15 * 12 = $180 per customer
Monthly fraud prevention cost: $5, so annual cost = $5 * 12 = $60 per customer
Per-customer annual profit = ($79 + $2 + $180) - $60 = $201
Total annual profit = $201 * 500,000 = $100,500,000

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.