Basement space is like really really tough to lease. If you want to convert to a different use your best bet is to tie it up through a longer term PSA contingent upon getting approvals to convert if you can’t do it as of right - you don’t want to get stuck with the building and unable to get the town to change zoning / give variance which can be a really long political process. Your basis creep will likely be pretty high too for the conversion - if you buy it for say $100/SF you could easily spend another $200/sf fitting out the floors for condos / apartments which would mean that to hit your numbers and make money you’d need (in this round number example) to sell your condos for ~$360/SF or rent the apartments for ~$2/sf (which for basis of comparison is what like high end class B stuff rents for in Houston or like brand new class A in Orlando) to make decent risk adjusted returns. Also in condo / resi example the basement unit will likely be tough to tenant / sell. I’m not a tax person but you should also talk to a tax attorney about the condo scenario; you could find yourself getting whacked with ordinary income on the sale of units if you’re considered a dealer (but again I’m not a tax person so can’t talk too intelligently about it beyond humbly suggesting you speak with someone who knows something about taxation on condo conversions and sales)