Call stretching is a method utilized by fraudulent carriers to inflate the duration of a call, and effectively charge more money directly from legitimate carriers. It is amongst the five most prevalent telecommunications schemes in the US and Canada. As telecom operators and government agencies work to target a specific type of fraud, more complex and innovative methods are utilized by scammers. Call stretching manages to bypass most skilled fraud management systems.¹

This is carried out in one of two ways. The basic scenario is continuing to keep the line active for several seconds after the call has been terminated by the other party. The more intricate scheme involves the recording of a portion of live conservation. A portion of the other party's voice is played immediately after the originating party disconnects. It often takes many seconds, or even a few minutes before the party realizes this and hangs up.

Although seeming minuscule, when conducted on a massive scale this method generates over a billion dollars annually.² Detection of this fraud is difficult as the call themselves are legitimate, and the profit per call is small. Because originating carriers measure pay out according to the duration of the call, they end up paying more to the fraudulent carriers than they actually owe. Recording a private conversation poses a massive breach in privacy. Call stretching results in carriers having to manage disgruntled subscribers and high customer turnover.

What is the solution?

If you are receiving a lot of these calls, report it to your phone provider. Don't feel obligated to answer each and every call from unknown numbers. It's important to remember that legitimate callers trying to reach you will often leave a voicemail. If you are expecting a call, and you aren't sure whether it is safe, use Whois by SIPSTACK. Entering the Caller ID displayed will instantaneously provide a score rating out of five stars, as well as other relevant information to help you determine whether the call is safe.

References

^{1 https://cfca.org/the-key-to-stopping-call-stretching-fraud-a-real-time-handshake-between-operators/
2 https://community.abhandshake.com/call-stretching}