Billionaires and rent-seeking companies. There are at least three national companies I can think of who are hoarding single-family homes in major cities and renting them out.

Generally they purchase at scale via REO scenarios, and provide no value whatsoever while driving up prices drastically

One example is a company called “Progress,” no better or worse than the others but with a meaningful web presence if you’re curious.

Kill the billionaires who horde homes.

It isn't the billionaires, it is the funds the billionaires and multimillionaires invest in. I have seen these funds buy under-privileged neighborhoods almost in their entirety in less than a year. They replace the cabinets with builder grade stuff they buy in bulk, same with the carpet, a few.light fixtures and a coat of paint (maybe $5k investment) and they rent them out to working families. A neighborhood goes from ghetto to starter within two years, but rents go from ~$800 to ~$2200 as well. Also, those homes will never be within reach for anyone looking to purchase.

I actually think we need to cap rent increases to about 2%. In a little over 14 years, your rent doubles at 5%. So $2.5k/mo becomes $5k/month- $60k/year! Since wages have largely stagnated, most renters would be in an even worse place (although definitely better than 10% increases).

https://media1.tenor.com/m/r5FOkTjCCfMAAAAC/hypnotoad-futurama.gif