The Apple Inc. logo is displayed on the back of the new MacBook Pro David Paul Morris-Bloomberg via Getty Images
By Abram Brown

Apple (AAPL) investors, a group recently characterized by pessimism on the tech giant's future, seemed Wednesday oddly out of character. They stopped short of a large sell-off in Apple stock despite a legal decision that could stop the sale of some iPhones and iPads in the U.S.

The U.S. International Trade Commission ruled that Apple violated a Samsung (SSNLF) patent over technology that sends information over wireless networks. An appeals court, or a presidential veto, could overturn the decision, but if the ruling stands, Apple products like the iPhone 4, iPhone 3GS, iPad 3G, iPad 2 3G and the iPad would be prevented from import onto AT&T's network.

Newer Apple products, such as the iPhone 5 and fourth-generation iPads, would be unaffected, and Apple quickly vowed to fight the ITC's decision. Apple's promise to push the case into an appeal's court kept Apple investors from panicking. Shares closed only a little down just 0.5% to $447, a time when the Nasdaq is off 0.3% to 29,966.50.

Other opportunities for concern about Apple's future in past months immediately sparked gloom from its investors. CEO Tim Cook struggles to define his tenure, taking criticism for mostly introducing product updates–and none of the flashy new product launches that propelled Apple to become the world's most valuable company and made Steve Jobs a Silicon Valley deity. Apple shares are down 19.9% in the last year. The Nasdaq, by contrast, has gained 25.4%.

The rivalry between Samsung and Apple, one-time business partners turned bitter rivals, creates a messy legal situation, in which both hurl accusations of competing patent. Apple last year won a jury trial and $1 billion in damages against Samsung. But Tuesday's ITC decision may force the two to consider a settlement.

Momentum increasingly shifted to Samsung in past months, as Google (GOOG)-powered Android phones greatly outsold Apple's iPhone. Indeed, 75% of the smartphones sold in the first-quarter were Androids, and Samsung accounted for 31% of those sales, according to Gartner.

If the ruling stopped some Apple sales in the U.S., a market that represents a third of sales, it would directly hit the $3.4 billion Apple takes in from the iPhone 4, according to Piper Jaffray's Gene Munster. The iPhone 5, by comparison, makes considerably more, some $14.9 billion.

More from Forbes