Flash Calls Are Silently Costing Telcos Billions — Here’s How to Fight Back
In the time it takes for a missed call to vanish from a user’s screen, your network could be losing valuable revenue.
This loss isn’t from traditional voice or data services — it’s happening through flash calls, the stealth disruptors of telecom authentication.
According to Juniper Research, operators stand to lose over $1.3 billion to undetected flash calls between 2023 and 2027. What may appear to be a harmless missed call is, in reality, a direct bypass of billable SMS verification channels, creating a silent but massive revenue drain for CSPs— and the threat is accelerating.
What Exactly Are Flash Calls?
Flash calls are ultra-short, machine-generated calls initiated for authentication purposes. Instead of sending a traditional one-time password (OTP) via SMS, certain apps trigger a missed call to the user’s number. The verification system then captures the last few digits of the incoming number to confirm the user’s identity.
No call is answered. No SMS is delivered. Most importantly for CSPs — no billable transaction occurs.
For OTT platforms, this approach offers clear advantages: reduced authentication costs compared to A2P SMS, faster and more seamless onboarding experiences, and improved conversion rates. However, for operators, it’s a growing problem — lost SMS A2P revenue, authentication traffic hidden within normal signaling flows, and limited visibility in CDRs.
Why the Threat Is Real — and Growing
A single operator can experience over a million flash calls in a month. Multiply that number across multiple carrier networks and regions, and the scale of revenue leakage easily reaches billions of unbilled events annually.
Because flash calls blend in with legitimate incoming voice traffic, traditional fraud detection tools and traffic analysis systems often fail to identify them. This invisibility benefits OTT providers — who save millions annually — but leaves CSPs to shoulder the costs of delivering authentication without compensation.
The adoption rate of flash call authentication is increasing rapidly. Industry data show that over 42% of organizations adopted flash calls for mobile verification in 2023, and global flash calling authentication volume exceeded 3.5 billion events — a 47% increase year-over-year. Many global technology companies are already testing or deploying it as their default onboarding method. Unless operators act now, the leak will only widen.
The Opportunity: Turn Revenue Leakage into Revenue Generation
While flash calls pose a significant challenge, they also present an untapped revenue opportunity. CSPs who can accurately detect, classify, and manage flash call traffic can not only recoup losses but also position themselves as key enablers of secure digital authentication.
By aligning flash call monetization with existing A2P SMS frameworks, operators can bill OTT authentication fairly, prevent bypass strategies, and even offer value-added authentication services directly to enterprises and digital platforms. This transforms the problem into a sustainable revenue stream while increasing control over authentication-related traffic.
Case Study — How One CSP Plugged the Leak
A leading telecom operator noticed a sharp, unexplained drop in A2P SMS volumes. On closer inspection, they uncovered a significant surge in flash call authentication traffic.
They took the following steps in collaboration with Subex’s Signaling Risk Intelligence solution:
- Detected and classified flash call traffic in real time, achieving 86% detection accuracy within six weeks
- Averted over $500,000 in annual revenue leakage that would have otherwise gone unnoticed
- Identified and monetized over 1mn flash call attempts per month
- Gained comprehensive analytics on OTT authentication behaviors
Return on Investment: Within six months, the operator recovered lost revenues and converted a hidden drain into a predictable, growing source of income.
The Strategic Blueprint for Telcos
Successfully tackling flash calls requires a shift in approach. Operators must invest in advanced, AI-driven signaling analytics capable of distinguishing flash calls from legitimate voice traffic. Real-time detection and automated billing frameworks are essential to turn these bypass events into revenue-generating transactions.
At the same time, CSPs should proactively engage with OTT platforms to establish fair usage and monetization agreements — similar to existing SMS interconnect arrangements. Regulatory coordination will also help ensure authentication channels are standardized and transparent.
The Time to Act Is Now
Flash calls are not a passing trend — they are fast becoming the preferred authentication method for many digital giants.
For operators, the choice is clear: Act now to stop uncontrolled revenue leakage, protect existing streams, and create new, sustainable sources of income. Or wait — and watch as your revenues quietly erode.
The question is no longer whether flash calls will impact your business.
It’s whether you will monetize them before someone else does.
Join leading operators who are already fighting back. Schedule a call with our specialists to explore revenue protection strategies today.
Vinutha V Rao Technical Product Manager, Fraud Management With 10+ years of experience in telecom and enterprise solutions, Vinutha is a domain expert in telecom fraud management, AI-driven analytics, and signaling security. At Subex, she leads the development and pre-sales of next-gen Fraud Management Systems (FMS), enabling top-tier operators across the globe to combat emerging threats in voice, SMS, and mobile money ecosystems.
