Apple is now America’s third-largest company by stock market value. Over the past three years, its shares have more than doubled in price, while those ofnumber one, Exxon Mobile, and number two, Microsoft, have fallen slightly. If that trend continues, Apple will be America’s largest company by year’s end, according to a “SmartMoney” report (http://www.smartmoney.com/Investing/Stocks/apple-may-soon-be-americas-largest-company/?afl=yahoo&hpadref=1).

Of course, just where Apple ranks by size depends on how you define size. If sales are a better measure of economic weight than stock market value, then Apple is No. 42 — four spots below Dell. However, “SmartMoney” says that may not be a fair comparison as Apple turns 29 cents of each sales dollar into operating profit, versus a nickel for Dell. And even ranked by net profit, Apple isn’t among America’s top 10 companies.

“That raises a common question about the stock: Have its popularity and price gotten ahead of its underlying economic value?” “SmartMoney” says. “To some, Apple shares look too expensive. But not to Wall Street’s prognosticators. According to a Thomson poll, 37 of 43 analysts who publish recommendations on the stock currently advise investors to buy. Among those fans are 15 who strongly recommend a purchase.”