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Author: Taylor Warfield, Former Bain Manager and Interviewer

Telecom case interviews are among the most common industry-specific cases you'll face in consulting interviews. If you're interviewing at any top consulting firm, there's a good chance you'll get at least one telecom case interview.
In this guide, I'll walk you through everything you need to know to crush your telecom case interview. You'll learn the essential industry knowledge, key terminology, and the types of questions interviewers commonly ask.
But first, a quick heads up:
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You don't need to be a telecom expert, but you should understand the basic industry structure and business model.
The global telecom market is worth over $1.7 trillion, and it touches nearly every consumer and business on the planet.
Telecom companies face constant challenges. They're dealing with infrastructure upgrades, new technology rollouts, intense competition, and changing consumer behaviors.
Telecom companies make money by providing communication services to customers. They charge recurring fees (monthly subscriptions) for access to their networks.
The business has high fixed costs and relatively low variable costs. Building and maintaining network infrastructure is extremely expensive, but serving one additional customer costs very little.
This creates intense pressure to maximize the number of customers on the network. More customers mean the fixed infrastructure costs get spread across a larger revenue base.
You should know the main types of players in the telecom industry:
Telecom companies typically have three main revenue streams:
Knowing these terms will help you sound informed and ask better questions during your telecom case interview.
1. ARPU (Average Revenue Per User)
ARPU measures the average monthly revenue generated per customer. If a company has $100 million in monthly revenue and 1 million customers, the ARPU is $100.
ARPU is one of the most important metrics in telecom. Companies constantly look for ways to increase it through upselling, premium services, or reducing discounts.
2. Churn rate
Churn rate is the percentage of customers who cancel their service each month or year. A 2% monthly churn rate means 2 out of every 100 customers leave each month.
Reducing churn is critical because acquiring new customers is expensive. It's almost always cheaper to keep an existing customer than to replace them.
3. Customer Acquisition Cost (CAC)
CAC measures how much it costs to acquire one new customer. This includes marketing expenses, sales commissions, promotional discounts, and device subsidies.
4. Customer Lifetime Value (CLV)
CLV estimates the total profit a company expects to earn from a customer over their entire relationship. If a customer pays $50/month, stays for 24 months, and generates a 40% margin, the CLV is roughly $480.
1. Spectrum
Spectrum refers to the radio frequencies that wireless networks use to transmit data. Governments auction spectrum licenses, and they're extremely valuable assets.
Different spectrum bands have different characteristics. Low-band spectrum travels farther but carries less data. High-band spectrum carries more data but doesn't travel as far.
2. 5G, 4G LTE, and 3G
5G, 4G LTE, and 3G are different generations of mobile network technology. Each generation offers faster speeds and better performance than the previous one.
Most telecom cases involving technology will focus on the business implications of upgrades, not the technical details.
3. Network infrastructure
Network infrastructure includes cell towers, fiber optic cables, data centers, and all the physical equipment needed to provide service.
4. Coverage
Coverage measures the geographic area where a network provides service. Companies invest heavily in expanding coverage to reach more potential customers.
5. Network capacity
Network capacity refers to how much data the network can handle at once. As customers use more data, companies need to add capacity to prevent slowdowns.
1. Postpaid vs. Prepaid
Postpaid vs. prepaid describes two different billing models. Postpaid customers pay at the end of each month after using services. Prepaid customers pay upfront before using services.
Postpaid customers typically have higher ARPU and lower churn but require credit checks. Prepaid customers have lower ARPU but attract customers who can't qualify for postpaid plans.
2. Bundling
Bundling means offering multiple services together at a discount. For example, combining mobile, internet, and TV service into one package.
3. Infrastructure sharing
Infrastructure sharing is when multiple telecom companies share the cost of network equipment like cell towers. This reduces costs but can create competitive concerns.
4. Unlimited plans
Unlimited plans offer unlimited data, talk, and text for a fixed monthly price. These plans have become standard in many markets and put pressure on ARPU.
Telecom cases typically fall into a few common categories. Understanding these will help you prepare more effectively.
These cases ask whether a telecom company should enter a new geographic market or launch a new service.
You might see questions such as:
For these cases, focus on:
Key questions to consider include market size, growth rate, competitive intensity, regulatory requirements, and infrastructure costs.
These cases focus on decisions about building or upgrading network infrastructure.
Common scenarios include:
For infrastructure cases, think about the business case for the investment. Calculate expected returns based on customer growth, ARPU increases, or churn reduction.
You should also consider the competitive implications. If competitors are upgrading and you're not, you might lose customers.
These cases ask how a telecom company can improve its financial performance.
You might encounter:
For profitability cases, use a standard profit framework. Look at revenue (number of customers times ARPU) and costs (fixed infrastructure costs plus variable customer costs).
Common solutions include reducing churn, increasing ARPU through upselling, cutting costs through network optimization, or acquiring competitors to gain scale.
These cases present a competitive threat and ask how the company should respond.
Examples include:
For competitive cases, first assess the threat. How many customers might you lose? What's the financial impact?
Then consider response options. Can you match the competitor's offer? Should you differentiate on quality instead of price? Would it be better to acquire the competitor?
Merger and acquisition cases are common in telecom because the industry has seen massive consolidation.
Typical scenarios include:
For M&A cases, evaluate:
In telecom, key synergies often include network consolidation, customer base expansion, and cost savings from eliminating duplicate infrastructure.
Let’s walk through a complete telecom case interview so you can see how all these concepts come together.
Our client is MobileConnect, a mid-sized mobile network operator in the United States. They currently serve 15 million customers and generate $10 billion in annual revenue. Over the past two years, they've seen their customer base decline by 10% while their two largest competitors have grown.
The CEO wants to understand why they're losing customers and what they should do about it. How would you help MobileConnect?
First, clarify the objective. You want to understand the root causes of customer loss and develop a strategy to stop or reverse the decline.
Ask a few clarifying questions:
Let's say the interviewer tells you:
Now structure your approach. You want to investigate:
The interviewer might share that customer surveys reveal three main issues:
You should probe deeper into each issue.
On network quality, you learn that MobileConnect has delayed 5G upgrades while both major competitors have rolled out 5G in major cities. Customers in those cities are experiencing slower speeds compared to competitors.
On pricing, competitors have launched unlimited data plans at competitive prices while MobileConnect still uses tiered data plans. Customers who exceed their data limits face overage charges.
On the younger demographic, MobileConnect has focused marketing on traditional channels (TV, radio) while competitors use digital and social media heavily. They also lack the digital-first account management that younger customers prefer.
Based on this analysis, you might recommend a three-part strategy:
1. Accelerate 5G rollout in the top 20 metro areas where customer losses have been highest.
This addresses the network quality gap.
Calculate the business case. If the investment is $2 billion and it reduces churn by 0.5 percentage points, you're saving 75,000 customers per month. At $55 ARPU and a 40% margin, that's $1.65 million in monthly profit or $20 million annually, giving you a 10-year payback period.
2. Launch competitive unlimited plans to match the market.
You'll need to model the revenue impact. Some customers will upgrade from cheaper plans (increasing ARPU), others will downgrade from expensive plans (decreasing ARPU).
The key is whether the churn reduction and new customer acquisition offset any ARPU decline.
3. Revamp marketing for younger customers through digital channels and influencer partnerships.
Redesign the mobile app and online account management to match competitor offerings. This is a smaller investment but critical for long-term growth as younger customers represent future revenue.
When you deliver your final recommendation, be clear and concise:
"MobileConnect should pursue a three-pronged turnaround strategy focused on network quality, competitive pricing, and customer experience.
First, invest $2 billion to accelerate 5G rollout in the top 20 metro areas. This directly addresses the network quality complaints driving customer losses.
Second, launch unlimited data plans to match competitors and eliminate customer confusion around overage charges. We'll need to carefully price these to balance ARPU maintenance with churn reduction.
Third, shift marketing investment toward digital channels and improve digital customer experience to attract younger customers.
I expect this strategy to reduce churn from 2.5% to 1.8% within 18 months, which would stabilize the customer base and return the company to growth."
Here are a few more telecom case scenarios you might encounter and how to think about them:
Case prompt: A large retail company wants to launch its own mobile service as an MVNO. Should they do it?
Key considerations:
Calculate the unit economics. If wholesale network costs are $25 per customer, retail price is $40, and operational costs are $10, you're making $5 profit per customer per month.
With 1 million customers, that's $60 million in annual profit. Compare that to the investment required to launch the service.
Case prompt: A telecom company is considering expanding fiber optic broadband to rural areas. How should they approach this decision?
This is fundamentally an infrastructure investment case.
Calculate the cost per household to build fiber infrastructure in rural areas. It might be $2,000 to $5,000 per household depending on density.
Estimate the penetration rate. What percentage of households will actually subscribe? Rural areas might see 30-50% penetration vs. 60-80% in urban areas.
Calculate ARPU and margins. Rural customers might pay $60-80 per month for high-speed internet with 50-60% margins.
Determine the payback period. If it costs $3,000 per home, you get 40% penetration, and you earn $30 profit per month per customer, you're looking at an 8-year payback period.
Consider alternatives like fixed wireless or satellite that might have lower infrastructure costs.
Case prompt: A mobile operator wants to develop different service tiers for different customer segments. How should they think about this?
Segment customers by value and needs:
Calculate the ARPU and churn rate for each segment. Focus retention efforts on high-value customers where the impact is greatest.
The best way to prepare for telecom case interviews is to practice with the concepts you've learned here. Here's a structured approach to build your skills:
You should be able to quickly calculate ARPU, churn impact, and customer lifetime value during a case. Practice working through sample calculations under time pressure, ideally with a partner who can throw variations at you.
For instance, try calculating the revenue impact of reducing monthly churn from 2.5% to 2.0% for a customer base of 5 million subscribers with an ARPU of $50.
The faster you can work through these mechanics, the more mental bandwidth you'll have for the strategic thinking that actually impresses interviewers.
Have a mental structure for market entry, profitability, and competitive response cases. Don't just memorize generic frameworks—adapt them specifically for telecom contexts.
For a market entry case, you might structure your approach around network infrastructure requirements, spectrum acquisition, customer acquisition strategy, and regulatory considerations.
For profitability cases, think through both the revenue side (ARPU improvement, subscriber growth, reducing churn) and cost side (network optimization, customer service efficiency, device subsidies).
Write out these frameworks on paper and practice delivering them out loud until they feel natural.
Spend 30 minutes reading news about major telecom companies like Verizon, T-Mobile, AT&T, Vodafone, or China Mobile.
You'll pick up on current industry trends and challenges that might appear in cases—things like 5G rollout strategies, fixed wireless access as a broadband alternative, or competitive dynamics in emerging markets.
Pay particular attention to earnings calls and analyst reports, which often discuss the metrics and strategic priorities that mirror case interview topics. This industry knowledge helps you ask more insightful questions and demonstrate genuine interest during your interview.
Nothing replaces live practice. Work through complete cases with peers, mentors, or your school's consulting club.
Focus on cases that specifically involve subscription businesses or network economics, even if they're not strictly telecom—think streaming services, SaaS companies, or utilities.
After each practice session, get specific feedback on your structure, your comfort with quantitative analysis, and your ability to synthesize insights into clear recommendations.
Telecom case interviews aren't as intimidating as they might seem. Once you understand the basic business model and key metrics, they follow the same logic as any other case.
Remember that telecom companies make money through recurring subscriptions. They have high fixed costs and low variable costs, which creates pressure to maximize customers and ARPU.
The most common challenges involve customer churn, competitive pricing pressure, infrastructure investment decisions, and market entry opportunities.
If you've practiced the fundamentals and familiarized yourself with industry terminology, you'll be well-prepared for any telecom case interview.
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