Next year the FDA will introduce new limits making the maximum allowable claimed SPF50+. Although before this change was flagged there was certainly a race for ever increasing SPF numbers in the USA. I can imagine some brand manager demanding an SPF200 product in a new product meeting, so why not...? - Cost. Sunscreen agents are expensive - Aesthetics, organic sunscreens feel horible and oily, inorganic suncreens would leave the skin too white - Diminishing returns. A SPF15 will block about 94% of UV light, SPF30 97%, SPF50 98%, SPF100 99%