Can someone ELI5, FHFA the affordability test concept for agency lending?
I’ve been trying to better understand this concept. For example, what does this mean: 

A property is 50% affordable at 100% AMI, which would be an example of a property in Los Angeles. What does the 50% refer to? I understand 100% AMI mean 100% of the median income of LA, which is around $70K per Google. 

Please and explain thank you!
[{"id": "iejrfg7", "text": "It means that 50% of the units have to be affordable to households making 100% AMI. You can find these figures on the State\u2019s TCAC website (don\u2019t use Google, actually find the data on a govt site that gives you the exact figures). There will be a rent and utility limit based on the unit size.", "replies": [{"id": "iejro6q", "text": "So that mean in order for borrowers to get the loan for that property, they have to rent out half of the total units only to people or families with incomes matching 100% AMI?", "replies": [{"id": "iekgfac", "text": "Definitely not as rigid. Any and a lot of affordability is good for the agencies. Warn ya though, there are too many variables so I would speak with an Agency rep to see where your individual deal shakes out for best rates.", "replies": [], "depth": 3}], "depth": 2}], "depth": 1}, {"id": "iekmze8", "text": "The main objective of the agencies is to provide financing that preserves affordable housing. As a result 65% of units they finance this year have to be at 80%ami as set by fhfa. \n\nThe more restrictive that preservation of affordability, the more attractive it is to the agencies. Meaning If the property has a regulatory agreement that requires them to maintain say 50% of the units at 60% of ami for the next 20 years, then that\u2019ll be more attractive then a property that just happens to have rents that are at those levels of affordability because it\u2019s a class C property in a high cost market (natural affordability)\n\nThe agencies will do both and finance properties with 0 affordability too, but all things the same, the pricing on the affordable properties will be much more attractive. \n\nSource: I work for an agency licensed lender and price deals all day based on affordability (among other factors). Pm me if you have more Qs.", "replies": [{"id": "ieml61h", "text": "What do you mean by 65% of units have to be at 80% AMI? 65% of the units referring to their rental rates have to total up to 80% of AMI on an annual basis?\n\nSo let\u2019s say 80% AMI of some state is like $30K. That means 65% of the units\u2019 rental income can\u2019t be more than $30K in total?", "replies": [], "depth": 2}], "depth": 1}]