One of the most popular top-level domains under the Uniform Domain Name Dispute Resolution Policy (UDRP) is not even a gTLD (generic top-level domain). It’s a ccTLD: .co, the country-code top-level domain for Colombia, in South America.

Based on statistics at WIPO as of this writing, 29 .co domain names have been the subject of UDRP disputes this year, making it the most-disputed ccTLD under the popular domain name dispute policy. The same has been true every year since 2010, when .co domain names apparently first became subject to the UDRP—11 years after the UDRP itself went into effect. Despite its late entry into the UDRP system, .co is in fact the most-disputed ccTLD ever under the UDRP (at least at WIPO), with 388 domain names in dispute.

(Granted, the number of .co UDRP disputes pales in comparison with the number of .com UDRP disputes: As of this writing, 1,464 .com domain names have been the subject of UDRP disputes this year at WIPO.)

At least 38 ccTLD operators, including .co, have adopted the UDRP, but only .co appears with any regularity in UDRP proceedings. Only the ccTLDs for Tuvalu (.tv) and Romania (.ro) rank in the top 10 among all ccTLDs for which WIPO administers domain name dispute policies.

So, why is .co (relatively) popular among disputed domain names?

The answer is probably obvious: .co is the top-level domain name that is most similar to .com. (While .cm, the ccTLD for Cameroon, is also only one character “off” from .com, the .cm registry has not adopted the UDRP.)

As a result, some cybersquatters find .co domain names attractive, hoping to catch Internet users who commit a typo by omitting the letter “m” when entering a website address.

For example, the following domain names, all of which have been the subject of UDRP disputes since last year, contain well-known trademarks:

• <autodesk.co>
• <traderjoes.co>
• <novonordisk.co>
• <7eleven.co>
• <publix.co>
• <skechers.co>
• <altria.co>
• <philips66.co>

In each case, the trademark owner that filed the UDRP complaint prevailed.

In one case, involving the domain name <sanofi.co> and the trademark SANOFI, a UDRP panel noted the obvious: “The Domain Name is identical to the Complainant’s mark… but for the suffix ‘.co’, which the Panel accepts is to be disregarded for the purposes of the present test. Accordingly, the Complainant has established that the Domain Name is identical or confusingly similar to a trademark or service mark in which the Complainant has rights.”

Not only is .co obviously similar to .com, but several years ago, when Colombia granted a third party the right to manage its ccTLD, .co suddenly became the subject of an intense marketing campaign, the result of which was “to spread awareness about .CO domain names within a community of frequent domain purchasers,” one writer said in 2012. The ccTLD even made an appearance in a GoDaddy Super Bowl TV ad “urging people to register a .CO domain before someone else snatches it up and gets rich doing so,” Adweek reported in 2013.

The arrival of hundreds of new gTLDs (a few of which have proven moderately popular) has since taken over most of the publicity around domain name availability. But .co remains a quiet threat to trademark owners, who obviously are filing UDRP complaints with success to recover these problematic domain names.