It is for new, transfer or renewal - the wholesale price of each .com to the registry.
However, sometimes the registry offer confidential bulk discounts based on a certain number of registrations. I am less clear, but I think there may from time to time be renewal bulk wholesale promotions to registrars, but I don't know this for sure.
So when registrars offer $6.50 transfer or the same price or less for registrations they are losing money on that transaction. Now many hope that enough will renew, or bring in money in other ways such as purchase of hosting, or be sold on the registrar marketplace and get a cut that way, but on the actual registration they are losing money even not counting their own costs.
If you look over the past decade, and compare the slice of the registration pie over actual costs, the legacy registries have a much larger share compared to a steadily shrinking registrar share. I hope, and think, I am reporting that correctly from a panel at NamesCon 2019. That is how the gross profit of Verisign is so high, and why there was so much concern when the four 7% per year increases were approved without it going to competitive tender.
Bob