Warrantable vs. non-warrantable, in plain language
Most loans in America are agency loans, meaning the lender follows the selling guides published by Fannie Mae and Freddie Mac. Those guides include project standards the condo association has to meet. When a building passes, the full menu of conventional loans opens up with the best pricing attached. When it fails even one standard, the conventional shelf disappears and portfolio banks take over.
Portfolio lenders lend their own money and keep the loans on their own books, so they can write guidelines that fit real buildings instead of a checkbox. In the industry these are called portfolio or non-QM loans, and they are the reason a non-warrantable condo is a detour rather than a dead end.

