That's interesting since Zillow bought Trulia in 2015.However, Trulia claims 65m unlisted home estimates and Zillow claims 110m.Both algorithms are supposedly based on physical characteristics, location, and recent sales.Zillow also correlates its Zestimate forecasts in with the ZHVI forecast for the ZIP / County / State.My best guess is that Zillow's numbers are more swayed by the general area and Trulia's are more based on the property itself.

We run algorithms on MLS data to identify and analyze potential investment properties.

On Zestimates, understand that their accuracy has more to do with the underlying data, like property type and location, then with the algorithm itself. 

.- they're telling me they have an algorithm they use with purchase price, carrying costs, closing costs as well as renovation prices that gives them the purchase price of $91,900.

There are enough bird dogs watching that they are going to find the hit just about as fast as your algorithm does.

I'm better on the data side and developing the heuristics and algorithms for obtaining actionable data sets.

So their algorithm has to estimate more.

Your algorithm would favor the tenant so they should not complain.

They get way more exposure and the algorithms favor videos.

I can't tell you how many times wholesalers have quoted me ARV values using Zestimates.Zestimates use an automated computer algorithm to try to determine price, the problem often comes into play when the website pulls comps that aren't really comparable.