Wolfe, Speculative (Spec) construction for ground-up investor construction isn't cheap and the Treasury has been climbing...and with them the rates on Spec Construction.

Follow the rate of the 5yr treasury bond. 

The purpose of this post is to understand the following:What changes to the purchase price for each annual rate will need to be to get the same principal plus interest payment.The impact on the loan term (15 year versus 30 year) and how it impacts the purchase price for the same principal plus interest payment.The impact on purchase price as the government raises treasury rates to combat inflation.

I would demand positive cash flow from every property you purchase, and that includes the opportunity cost on any funds that you invest in the property that you could have invested elsewhere, such as in Treasury bills.If you're still negative even at that low interest rate, how is that property ever going to cash flow?

I asked him what he was going to do with the proceeds and he was going to buy 10 year treasuries.  

You could put that into treasury bills that are yielding 5.25%+ That would give you close to $100,000 for 0 operating expenses and effort (e.g. no real estate tax, maintenance, property management costs, etc.)Similarly you can put it into the market which on average has garnered 7%+ returns.

Treasury bills are paying 5+% and investment grade muni bonds are paying 8% - 9% (assuming u are in the highest federal tax bracket and in a high tax state like NJ).

Unless the closing costs are crazy high, I don't know why they just wouldn't just purchase a 30-year US Treasury at 3.696% (risk-free).

It's a process set out by statute and a high-level summary of the foreclosure portion is: (1) starting 3 years from the date of the tax lien sale (but not more than 10 years) and after having sent the required notice, the holder can file a foreclosure action; (2) assuming the holder can show the tax lien sale properly occurred and there has been no prior redemption, the judge orders the county treasurer to issue a treasury deed in the holder's favor, subject to right to appeal.

Also, the 10 year treasury note which can be seen as an indicator for rates hit it's highest level in years yesterday.