When I built my enterprises, I never stopped building and I didn't bother to transfer money to pay off the debt. I already knew my corporations would be profitable, so paying back the loans would be a matter of time.
I racked up 35T in debt while building 750 corps. Eventually, it was all payed away and I now transfer 5T out of the enterprise every week.
I have not bothered to keep my myself up to date, but I believe the rules are now different from when I finished building my last enterprise. The initial capital of all corporations was 100B, I could build corporations even when my enterprise was in debt and enterprises weren't forced to inject capital into when corporations we're at loss; so young, unupgraded corporations could keep their debt, instead of having it transfered to the enterprise in practice.
For that last aspect I mentioned it may be why you are still making a loss: your corps are not fully upgraded. It
Build, build, build huh!!! WOW!! I racked up 1T in debt and started to freak out.
I have auto upgrade but havent done alot of super upgrades via the gold coins.
I build my corps based on the demand by world trade. Im assuming that isnt the best idea.