Many of the older furnaces are better built with cast iron heat exchanges, versus steel in later models and have no electronics to fail.

When I google Economic vacancy, that appears to basically be the same thing, except it includes things like giving a free month of rent and model units.Is that what you are talking about, or should I be looking at something else?  

Let's do the math - presuming a 50/50 split between the brokerage and agent (my best guess)Their model: a $400,000 home generates $4,000 in gross commissions and $2,000 for the agent.  

The goal of the research was to model secondary and tertiary markets that were similar to areas like Raleigh, NC, Salt Lake City, UT and other secondary/tertiary markets that had seen major growth since the recession; then try to pinpoint where the institutional capital started to emerge. https://1drv.ms/f/s!

In our model, we are assuming refinancing the first two properties after Year 1 by cashing out our initial $1M investment in each, and then reinvesting that $1M into another 30-40 unit complex at a ~$3M price.Basically: Year 1: Two properties at $1M eachYear 2: Refinance both properties, get initial $2M out of each property, and reinvest in another 2 like properties (4 properties at end of Year 2)Year 3: Refinance both recent properties, get initial $2M out of each property, and reinvest in another 2 like properties (6 properties at end of Year 3)Year 4: Refinance both recent properties, get initial $2M out of each property, and reinvest in another 2 like properties (8 properties at end of Year 4)Our model is to do this until Year 10. 

There may be one-offs but that is not a business model. 

I am a big advocate of modeling the teachings.

If it is a business model where the intent when purchasing the notes is to acquire and flip the property, then UBIT would need to be factored into your returns.Keep in mind, that exposure to UBIT just means there is a cost for your IRA to engage in a certain type of (hopefully more lucrative) activity.  

In my market, there is a 3rd party property management gap in the 10-75 unit space that the apartment specialists largely do not service...their model requires on-site management.  

Most I know doing this are doing it for local flips, which I think is likely the most appropriate business model for new acquisitions in SoCal today.