It's between the lines - EU prefers or demands GAAP/conservative especially for startups versus financial engineering/stratospheric approach to growth in the US.
Valuation for investment purposes and GAAP for accounting purposes are quite unrelated. Valuation is the art of estimating future cashflows, GAAP is the practice of reporting current cashflows that are comparable between firms. Obviously, valuation gets easier when the accounting is "more" GAAP. But just as firms are allowed to report all kinds of non-GAAP measures to further enhance their attractivity, the valuing party can use all kinds of measure, like future growth rates or debt schemes to enhance the valuation (caveat emptor). So there might be a huge difference in valuation and P/E between EU and US, but GAAP has little to do with that. In second order effects we could discuss whether US GAAP vs IFRS has an effect on how aggresively investors can account for these investments but I don't think that's the main driver of what I look at as runaway valuations in the US.
Edit: Seeing the rest of the thread. If the valuation seems low I'd expect that the due dilligence turned up some nasty things that where not in line with the non-GAAP financial statements of Infobit in the past. I couldn't find any audited financial statements. € 700 mln. revenue with growth potential at 18% margin does not lead to a € 1 bn. valuation in the absence of red flags.
Edit: Seeing the rest of the thread. If the valuation seems low I'd expect that the due dilligence turned up some nasty things that where not in line with the non-GAAP financial statements of Infobit in the past. I couldn't find any audited financial statements. € 700 mln. revenue with growth potential at 18% margin does not lead to a € 1 bn. valuation in the absence of red flags.