That explains things a bit

It's Apple's fault that the Nexus 6 doesn't have a fingerprint sensor (The Verge)

Former Motorola CEO Dennis Woodside has confessed that the dimple at the back of the Nexus 6 was originally intended to play host to a fingerprint sensor. Back in 2011, Motorola was a pioneer in bringing fingerprint recognition to its Atrix 4G smartphone, however the company it used then, Authentec, was purchased by Apple a year later for a price of $356 million. Authentec were, in Woodside's judgment, the best supplier around and "the second best supplier was the only one available to everyone else in the industry and they weren’t there yet."

Face.com Redux? AuthenTec to ditch non-Apple customers in 2013

AuthenTec to reportedly ditch non-Apple customers in 2013 (Apple Insider)

In an email to its customers, which includes Samsung, HP, Dell, Lenovo and Fujitsu, Apple acquisition AuthenTec reportedly said it will no longer be honoring orders come 2013, a source told Korean language website etnews.

The announcement may be an indication of what Apple plans to do with the company and its technology after purchasing the firm in July for $356 million. AuthenTec is well known for its work in fingerprint sensor tech and it was rumored that Apple might be looking to implement the biometric security asset into an upcoming iPhone.

It may be recalled that after Facebook bought Face.com, Face.com's existing customers were left twisting.

This is always a tricky post merger call. Does Apple continue to sell a technology, at a hefty profit, to its competitors? How long would Apple's competitors live with that deal?

Apple seems to have made the call.

Recent SEC Filings Reveal More on AuthenTecApple

Apple may put fingerprint scanners in future products (V3.co.uk)

Among the technologies Apple now owns is a type of fingerprint scanner designed for mobile products with Near Field Communication (NFC) built in. AuthenTec's AES2750 product is a fingerprint scanner that can interact with NFC applications to offer a secure way to log in to various systems.

AuthenTec says the technology can lock and unlock a phone, authorise mobile banking transactions and replace website user names and passwords, all with a fingerprint scan.

SEC filing fans rumors of mobile wallet for iPhone 5 (COMPUTERWORLD)

But how quickly these elements are introduced depends on Apple's long-range plans for iPhone, and iPad, as well as the maturing of the mobile payments industry infrastructure, a big jump in consumer acceptance and -- most of all -- trust in the new technology, and how quickly Apple can phase these particular technologies into its supply chain and manufacturing processes.
...
The fingerprint sensor, many speculate, will be a key part of a full-fledged mobile "digital wallet" using a near-field communication (NFC) radio link to trigger purchases by simply waving the handset over an NFC reader. AuthenTec, an established vendor of a range of smart sensors, identity management (including PC/laptop fingerprint sensors), and embedded security products, announced the deal on July 27. At $365 million, it's Apple's biggest buy.

It's worth pointing out that Josh Franklin at Seeking Alpha predicted the broad outlines of this whole thing a couple of months ago.

NFC + Fingerprint Biometrics = Cha-ching?

Apple wanted AuthenTec's "new technology" ASAP for future products (Ars Technica)

There's a hint that, whatever the tech involved, we won't have long to wait. According to AuthenTec's account, Apple wanted to hurry the buyout deal due to its own plans. "Representatives of Apple also noted Apple’s desire to proceed quickly due to its product plans and ongoing engineering efforts," reads the SEC filing. "As a result of its focus on timing, Apple’s representatives also informed the Company that Apple would not participate in an auction process and would rescind its proposal if the board decided to solicit alternative acquisition proposals for the Company."

More on Apple's AuthenTec Acquisition

Apple Buys AuthenTec To Boost Mobile Security (Tech Week Europe)

Q:
Why Apple?
Why Biometrics?
Why AuthenTec?

A:
ID management on mobile devices
NFC (near field communication) technology needs a backstop
Samsung

The linked article is, itself, full of useful links for piecing together what Apple's up to.

UPDATE:
A more biometrics-intensive focus can be found here: PC World.

Apple Buys AuthenTec

Apple acquires biometric firm for $350 million (San Antonio Business Journal)

Apple Inc. has reportedly paid $350 million to acquire Melbourne, Fla.-based AuthenTec Inc., a maker of fingerprint authentication technology, Bloomberg reports.
...
The deal will help Apple improve its biometric features to improve security on future releases of the iPad and iPhone.

For some perspective, Safran bought L-1's biometrics business for $1.6 billion in late 2010.

Josh Franklin at Seeking Alpha deserves a special prize. He called it here on June 4 when AUTH shares were trading for about $4.60/s. Pre-open today is about $8.16. Since his article at the time disclosed his long position in AUTH, he's probably already counting his special prize as I type this.

The Seeking Alpha piece explains a lot of the rationale for the purchase.