It always drives me crazy when my Magic 8-Ball answers my query with, "Better Not Tell You Now." I'd rather just have it break the bad news to me. I'm a big boy. I can handle it.

The same is true when it comes to stocks. The ideal is that companies are transparent with shareholders. This is why Lululemon Athletica (Nasdaq: LULU) bothers me. The company does not break out its sales-per-square-foot numbers separately for its U.S. and Canadian stores. There's no law that says it must, but in my opinion, there's really no good reason not to, either.

The reason I'm concerned is without that number, how can investors tell how well the newer U.S. stores are doing or place a value on the company?

While looking at other retailers, I noted that Home Depot (NYSE: HD) doesn't break out sales per square foot in different geographies. Neither does Gap (NYSE: GPS). However, neither of those icons is relying on the U.S. market to fuel megagrowth. They aren't really growth stories anymore -- Gap hasn't had double-digit revenue growth since 2001, while 2005 was the last time for Home Depot. Lululemon is a growth story (it grew revenue by 28% last year), and that's why I think this information is relevant.

The takeaway is that without that information, estimates of growth in the U.S. are hampered, which affects valuation models. That makes the valuation exercise even more uncertain than it normally is, and people like you, me, and Wall Street analysts will misjudge growth. And that leads to misjudging the intrinsic value of the company.

C'mon, Lululemon. Help out your shareholders and reveal what sales per square foot are in the U.S. and Canada. There's no real reason not to.

Matthew Brown doesn't hold stock in any of the companies mentioned in this article. He uses his Magic 8-Ball to make all of his important decisions in life. Home Depot is a Motley Fool Inside Value pick. Try any of our Foolish newsletters today, free for 30 days. The Motley Fool has a disclosure policy.