There’s an old adage in the domain name industry that a .net domain name is worth 10% of the same .com. Some also like to say that other extensions (.biz, .info, etc.) are worth 1% of the .com’s value.
The problem is it’s simply not true. Or rather it’s impossible to determine. The main problem is that the sample size is too small. Believe me, I’ve tried too look through the data and figure out what these ratios are. Here are the problems I’ve run into:
1. Finding .com domain sales that have sold in other extensions and where both sales were made public is extremely challenging.
2. Comparing a .net domain sold to a domainer and .com sold to an end user (and vice-versa) is like comparing apples and oranges.
3. A .net (or .org) domain might be generally more accepted in a certain industry (such as ISPs and .net) than in others.
Having looked at many samples, I’ve found the ration to be all over the place. If one company were to have to data to solve part of this equation, it would be NameMedia. But even that would be limited to a small segment.
About the only thing I can say with certainty is that .com domains sell for more than their peers. But to put a ratio on it just isn’t feasible. You need to look for another way to express value in your non-.com domains.