I have a confession to make about IPOs: whenever I hear that a fast-growing company is finally coming public, my first reaction is excitement. My second reaction is immediately wondering how much of that excitement Wall Street has already stuffed into the price. Oura is a perfect example. The smart-ring maker is preparing to trade on Nasdaq under the ticker OURA , and on the surface, there is an awful lot for me to like about the business. Revenue is exploding. Membership is growing even faster. The company is profitable. Its brand has become nearly synonymous with the smart-ring category. And, perhaps most importantly, Oura increasingly looks less like a company that sells expensive pieces of wearable hardware and more like a recurring-revenue health platform that happens to begin the customer relationship with a ring. Then I look at the proposed valuation. And my enthusiasm suddenly develops adult supervision. Oura and existing shareholders are offering 50 million shares at an expect...