[mstachowiak]

In Tesla case, it's because the non-GAAP numbers represent how they view and make decisions about their business internally. It makes them look better in some dimensions and worse in others. They report on it because it gives insights into how they think about things.

[refurb]

Based on the analyses I've read, it looks like a big driver of the non-GAAP difference is Tesla completely ignoring the cost of acquiring SolarCity. Is that a fair analysis? It depends. Those non-GAAP numbers suggest the car manufacturing business is doing well, but hide how Tesla is doing overall (including cash flow) as a result of SolarCity.