The Justice Department on Thursday concluded its antitrust trial against Apple over alleged price-fixing of digital books, with a federal prosecutor saying the creator of the iPhone and iPad engaged in an "old-fashioned, straightforward" conspiracy and Apple's lead attorney warning that a ruling against the company would "send shudders throughout the business community."

U.S. District Court Judge Denise Cote's ruling in the Justice Department's first major antitrust trial in more than a decade is expected to have broad consequences for the Internet economy.

The Justice Department's action against Apple, which it calls the "ringleader" of a cartel with book publishers to raise e-book prices, demonstrates the Obama administration's desire to create clear rules for powerful Silicon Valley firms that have been largely unbridled of regulations.