Tracing why a domain name expires can be interesting

[Arpit131]

What are some common reasons a domain name expires?

• The past owner didn’t need it any more and may not have considered it to be an asset or something they could “sell”.
• Bounced email notification of the domain expiring
• Expired email address associated with the domain / account
• Expired credit card on file for an “auto renew” feature
• Lost in the mix

The last one is often a reason some very valuable domain names expire!

An interesting article!

Complete article may be found here

 

[DNScholar]

Most likely reasons are 3rd and 5th.
I want to add "inventory cost" too one of the reasons for downsizing portfolio.

 

[korganian]

Many times it's because their credit card expiration date changed or they got a new email because they moved out of the area serviced by the ISP associated with that email or they simply died.

 

[Michael R.]

Sorry to add another reason, really sad: when the owner passed away.
A few premium .com have expired because of that these last years.