Mid-Sized Multi-Families in Chicago, What am I Missing?

[Will Johnston]

I live and invest in DC, but I'm from the Chicago burbs, so every now and again I Redfin properties in Chicago.  The other day I'm browsing around the Austin neighborhood on the west side, and I find a bunch of multi-family properties that aren't selling but seem like no-brainers.

I'm finding places listed at $450k, with gross rents of $15k. Even assuming 60% expenses and a 30% down mortgage at 5.5%, you're looking at like $4k/month cash flow, or a 35% CoC return.

I've got a friend who lives in Austin, so I've spent some time there and know it isn't exactly Chicago's premier neighborhood, but it doesn't strike me as a terrible area either.  And these numbers seem sick.

So I've gotta ask, what am I missing?  I haven't done any multi-family, so are my numbers off somehow? This just seems too good to be true.