After being a long-time hold-out, The Wall Street Journal has finally agreed to sell digital subscriptions through Apple’s Newsstand. The all-digital package is priced at $21.99 for the first three months.

Previously, the Journal only sold its downloadable apps through iTunes. It refused to be on the Apple Newsstand and refused to sell subscriptions.

It’s unclear what prompted the switch, but multiple publishers have been frustrated with Apple’s rules that require a 30% cut and don’t allow publishers to access customer data, such as names, email addresses or credit card numbers.

It’s also an unlikely move given that the iPad’s market share has been decreasing as new, more affordable devices enter the market.

The most likely reason, however, is that WSJ has strong confidence in its own marketing and subscription sales conversion — and is pushing its “All Digital Access” package. According to Apple’s rules, a publisher can sell subscriptions through its own site for iPad apps, including bundled packages. Those subscriptions, however, are not subject to the 30% cut.

In other words, whatever WSJ is doing to market its own product may be so strong, on-site sales will inevitably outweigh the negligible loss of revenue through Newsstand sales.