If two companies have the same historical and projected financials, same management team, same industry, and same strategy, why might one company be trading at 10x EV / EBITDA and the other company at 12x EV / EBITDA?

The company trading at the higher multiple is more valuable likely for qualitative reasons, since the historical and projected financials are the same.

For example, the company trading at 12x may have a more diverse customer base and therefore less customer concentration. The company trading at 10x may rely on only a few large customers, and if one of those customers leaves, it would result in a big revenue drop.

Another example is regarding the certainty of revenue. The company trading at 12x may have 3-5 year contracts with their customers, so their future revenue is contracted and has a high certainty of occurring. The company trading at 10x may have one-time customers that rarely repeat, so there is a higher risk that they can’t achieve their projected revenue.