What is the largest company that has ceased accepting fiat payments in favor of Bitcoin? We know there are many large companies that now accept Bitcoin transactions (Dell, Overstock, Expedia, etc) however they still accept fiat payments from legacy credit card systems.

Which large companies that have integrated Bitcoin transactions have now stopped supporting fiat payments?

Please exclude companies that never accepted fiat payments and were founded with solely Bitcoin support.
The largest company that accepts Bitcoin, and no longer accepts fiat, is BackPage. However they didn't stop accepting fiat of their own choice, but because Visa and MasterCard blocked them from accepting fiat.