An exclusive partnership for the enterprise market between Apple and IBM brings complementary skills from both sides – and poses some uncomfortable questions for a host of rivals.

“If you were building a puzzle, they would fit nicely together as puzzle pieces with no overlap,” said Apple CEO Tim Cook of the two new partners in an interview with Re/code.

The two companies were historic foes in the PC era but have competed virtually nowhere in the more recent mobile-dominated world, easing the path to partnership.

They will develop industry-specific apps to load on iPhone and iPads, which IBM will then sell to corporate clients.

Competitors including BlackBerry, Cisco and Microsoft might be worried. How Google might react is intriguing too.

It’s become a favourite sport to predict Apple’s next move: health, IoT and payments have all figured on the list but no one predicted the enterprise.

Apple has little background in the corporate market compared to IBM. Historically, few companies have managed to straddle both consumer and enterprise markets.

Apple and its new partner will jointly develop more than 100 new apps for various industries including retail, healthcare, banking, travel and transportation, telecommunications and insurance. The apps will become available starting this autumn – when iOS 8 is launched – and into 2015.

It’s rare for Apple to partner, and IBM appears to be contributing more to the relationship. It is making 100,000 of its staff available to back it up.

The enterprise giant’s cloud services will be optimised for iOS including mobile device management, security, analytics and mobile integration.

The apps will carry the IBM MobileFirst for iOS brand, an extension of IBM’s existing MobileFirst initiative to makeover industry-specific solutions for mobile devices.

There will also be a new version of the AppleCare service and support that is tailored for corporate customers, and delivered by IBM staff.

Finally, there will be new packages from IBM for device activation, supply and management.

Financial terms were not disclosed.

“When you put our teams in the room together, we both have engineering cultures, so they feed off of one another. And when you do that you end up with something better than either of you could produce yourself,” Cook told Re/code.