Prices for struggling offices would have to drop almost 50% to make conversion economically viable.

The change involves a broader and more expansive view of the asset class.

Real average weekly earnings cooling, up only 0.5% year over year, but that's less than in January.

The firm uses a net present value analysis, Treasury bond yields and forward inflation expectations to model TI allowances.

That's the first time in 2.5 years, according to Trepp. And retail was supposed to be doing well.

It's all about extended bonus depreciation that buyers of certain properties could gain.

But recovery is probably on the way as the category has been the least hurt.

Trepp examines how the same structural problems facing high-profile office properties are also found in smaller ones.