I have seen on some forums where people sell very good domains for $15 or so. What is the reason behind it ? Others will easily pay $ 150 - 200 for such domains. Maybe even more.
I think the best guess is that those domains are misused. Either by SEO companies or by people who do internet fraud. Just like getting rid of tools used for murder / burglary they disposing of those domains.
What do you think ?
Some are genuine. So just like you mentioned. Some of them are from the " bulk buyers ". When they make enough profit ( or loss ), they will try to get rid of domains that are in stock.