The Francisco Municipal Transportation Agency (SFMTA) recently announced it was considering selling the rights to name certain subway stations. If the SFMTA has its way, new companies will line up to pay millions to get their names affixed to public transit stations throughout San Francisco. After all, putting company’s name in a highly trafficked area where thousands of people are likely to see it seems like great advertising.   However, what these companies may not know is the effect these corporate names have on the stock market. The stock market is full of superstitions and myths. Day-to-day swings in the market often have more to do with fear than economic determinants. The market reacts to signals and signs-and when a company spends millions of dollars to put its name in lights, it has historically been a sign to sell.   The worst-case scenario is the National Hockey League's St. Louis Blues. In 2000, the team sold naming rights to its arena to Savvis Communications, an internet company, for cash and shares of Savvis stock. The company's stock has dropped 80 percent since then, and the team has lost millions. Unless their stock rebounds in the near future, the Blues may not be able to pay players or coaches, let alone continue to pay for the stadium.   The Blues 'experience is not unique. In fact, this chain of events has become something of a familiar pattern. So why do companies continue to sponsor such corporate titling? Perhaps the motivation is a marketing plan gone awry. Or perhaps these corporate names just mirror the vain desires of CEOs to see their corporation's name large in lights. In either case, it is the portfolio of the investor that suffers in the end. Publicizing the corporate name does not always raise the corporation's value. In fact, the opposite is often the case. If marketing departments were to study the history of such corporate sponsorships, perhaps they would think twice about such ventures in the future.