Bloomberg Businessweek is testing a question: How well can magazine content work on the iPhone?

Magazine companies have jumped feet first into the iPad marketplace, attracted to the idea that a lean-back medium like magazines would work well in a lean-back platform like tablets. But they’ve proven less interested in jumping onto iPhones and other smartphones — a target market that, while possibly less magazine-friendly, is also much larger.

The Bloomberg Businessweek+ app crossed that divide with a new version that jumps from the iPad to the iPhone, delivering the same issue-based content in a smaller package.

As on the iPad, Businessweek offers magazine articles, videos, audio interviews, and more; new issues of the magazines are downloaded into the Newsstand. Aside from obligatory design differences, the apps are identical in content; neither offers the regular updating of a daily news app.

The company says the app, which launched this time last year, has gained more than 100,000 subscribers on the iPad. The iPhone version is an attempt at opening up that number a little further. Oke Okaro, the global head of mobile for Bloomberg, told me it only makes sense to put its product on a device people have with them at all times. “Every waking hour of the day, smartphones are in our hands. We fully expect that we’re going to see a different type of usage,” Okaro said.

Bloomberg did add one new element in the iPhone app: it gives readers a word count for stories, making it easier to pick out the most digestible piece given whatever amount of time you have. “We know through the course of the day on iPhone people are going to come in and out, and we want to give them a perspective of the (time) commitment,” he said.

One feature both versions share is the ability to play audio in the background, whether reading a story in the app or doing other tasks on your iPad or iPhone. Okaro believes that would be handy to someone reading on a bus, the subway or waiting for an appointment. In other words, someone most likely using a smartphone.

Bloomberg will be watching the usage of the iPhone app closely and will likely solicit feedback from readers in the future. There is a fair share of overlap in the iPad and iPhone audiences, which is why the company chose the path of content parity. But that doesn’t mean Bloomberg wouldn’t be open to making changes to the iPhone version. “One of the things we’re going to kick the tires on is, are they interested in getting the stream of latest news from us?” Okaro said.

Since the iPad version of the app has been out for some time, Bloomberg has data on their readers’ habits, and they generally line up with what we’ve seen elsewhere: People are reading the magazine in the evening and on weekends. The magazine has grown a steady stream of new subscribers and converted print readers to verify their subscription, so the iPhone edition is a play at expanding their audience. Two factors that should help: iPad and iPhone users get a free issue of the magazine for downloading the app, and, maybe more importantly, Apple’s Newsstand, which automates issue distribution and assembles subscription content in one prominent place on iPads and iPhones.

Okaro said he’s undecided about the power of Newsstand. The seamless payment, visibility, and background downloading (only 3 minutes over 3G for their magazine, Okaro tells me) provided by Newsstand help magazines, but it also means giving up some individuality, he said. “Discoverability means you went from being one tap away from your favorite magazines to a few taps,” he said.

As a company, Bloomberg is trying to invest in finding what Okaro calls the “sweet spot” for readers, that perfect mix of stories, function, and usability to fit on whatever device they have in front of them at the moment. For Bloomberg Businessweek, the goal will continue to be to find the best way to serve magazine readers, whether they want to listen to a listen to listen to an audio report on Apple’s ongoing legal beef with Google now or read a 3,288-word piece on Buzzfeed’s advertising model later. “With all of our experiences, it’s paramount we provide people with appropriate perspective around whatever it is they are reading and give the opportunity to dig deeper if they choose,” Okaro said.