Black Friday was another disappointing event, at least as far as early data suggests.

There are many firms releasing reports on Black Friday, and pretty much all of them are negative. For instance, ShopperTrak notes that Black Friday was a “positive” for retail, but did not see any significant growth in Black Friday traffic relative to years ago. As a result, shopper visits to stores fell 1% year over year.

RetailNext, another data firm, said sales and traffic at brick-and-mortar stores fell from a year ago as a result of a more extended sales period and competition from online sales. They saw a 5% decline in store sales from a year ago during the Thanksgiving period, including Thanksgiving Day and Black Friday.

At the same time, online retail sales for the period rose by double digits. It seems that consumers haven’t lost their taste for Black Friday shopping, but they have lost their taste for Black Friday crowds. This isn’t surprising for the obvious reasons.

On the surface, this trend sounds like bad news that should hurt retailers immediately. We may even see a hit to retail stocks when they start to trade this week. But that doesn’t mean there’s a trend or a long-term movement to come, and it doesn’t mean retail stocks weren’t priced to expect such movements.

When one looks at the P/E ratios of retailer companies, one sees low growth broadly priced in. Target’s (TGT) P/E ratio is 14.4. Kohl’s (KSS) is 16.8, Macy’s (M) is 20, and Wal-Mart’s (WMT) is 15.5. The only exception to this low-P/E retail world is Costco (COST), whose P/E at 28.5 is above the S&P 500 by a high margin. But COST is still growing at a rapid rate, thanks in part to international expansion, and it isn’t even a popular destination for Black Friday sales anyway.

So we can’t really make any long-term investment decisions based on the Black Friday news–and this is an important lesson.

Many retail investors make snap trading decisions based on seasonality. That is to say, they will buy and sell stocks because they believe recent seasonal events (Black Friday, warm weather in the summer, the holiday season) will have a fundamental impact on a stock price for the long term. However, because these events are seasonal (i.e., they happen once a year and are more or less predictable), the market usually prices them in unless there is a shock to the system that changes the nature of these seasons. For example, if the U.S. government passed a law making Black Friday sales illegal, that would fundamentally alter the nature of the seasonal phenomenon. But changes in consumer activity around seasonal activities build up over a period of several years in most cases, meaning that the market slowly evolves to price them into the stock.

Black Friday is an excellent example. This has been declining in cultural value in America for years. Online shopping has extended the sales period, and growing popularity meant retailers took savvy, even cynical, methods to profit from a day that used to be more about margin sacrifice than revenue growth. As a result, the popularity of Black Friday has been on the decline for years, and the market has been expecting this for a long time.

So the disappointment of this Black Friday is really no disappointment–it’s old news. And it’s not something that will massively move stocks anytime soon for very long.