determines the socially optimal certification authority but also the type of certifier that is most likely to enter in … equilibrium. The theory's predictions are empirically testable and shed light on the variety of certifiers across markets and over …

choose a common standard if they can coordinate their quality provision. The actual investment then depends on the cost of … quality provision: If rather high, platforms refrain from investment; if rather low, platforms maintain vertically …, quality competition of standardised platforms induces the highest investment and maximum welfare. …