The rise in vacancies across Seattle is directly linked to the rate of newly constructed apartments, according to Capital Economics, and it’s increased from 5.2% at the end of 2019 to 7% by midyear 2023. Already, Seattle’s asking rent growth rate is at -2% and could fall further.
I'd really encourage people to actually read the article too. This is a direct consequence of increased construction, and just another piece of evidence to add to the rapidly growing pile showing that adding new housing stock - of any and all kinds - does cause a reduce pressures on rent.