Intel Corp. Senior Vice President and CEO and Chief Technology Officer of Mobileye Amnon Shashua (L) speaks in front of a Ford Fusion with Mobileye autonomous driving technology during a keynote address by Intel Corp. Getty Images

The promise of self-driving cars has gone mainstream, and this week's massive CES trade show was proof. Amazon, Intel, Nvidia and Cisco all made announcements about autonomous driving at CES, joining a host of rivals and partners that have publicly reported their efforts. To accommodate, the annual Las Vegas trade show expanded its space for self-driving technologies this year by over one third. They're coming late to the game: Alphabet's Waymo, Elon Musk's Tesla and the auto giants have all been developing self-driving technology for years. But nearly all the major tech companies now agree that the market potential is too big to ignore. Here's where the 12 most valuable U.S. tech companies are focusing their investment in autonomous driving, ranked by market cap from biggest to smallest.

Apple

Apple CarPlay. Source: Apple Inc.

Rumors of an Apple Car were put to bed last year when CEO Tim Cook said the company was working on "autonomous systems," or software that could power self-driving cars. That was a relief to investors who worried about Apple taking on Tesla, Toyota, GM and other car manufacturers. Cook hasn't made firm promises about self-driving technologies or dates by which they'll hit the market. Apple is partnering with Hertz to test its autonomous software in some of the company's rental cars (Lexus SUVs) on the streets of San Francisco, according to filings with the California Department of Motor Vehicles. Siri, CarPlay and other Apple software will probably get more usage once autonomous vehicles become a reality and drivers are free to pay attention to their screens, not the road.

Alphabet

Google has been talking up autonomous vehicles since 2009 when Sebastian Thrun launched the company's groundbreaking driverless car effort. In late 2016, Alphabet renamed its self-driving car unit Waymo. Seen as a leader in the nascent industry, Waymo is building an end-to-end self-driving system filled with sensors and software so "you can go door to door without taking the wheel," as its website says. Waymo claims to have 4 million miles of real-world driving experience and data gathered from cities including Mountain View, California, as well as Austin and Phoenix. Waymo has an early-rider program in Phoenix that lets people use its autonomous cars for their daily transportation needs. It's teaming up with Avis to make the vehicles rentable. The company has also partnered with AutoNation to provide vehicle maintenance and support, and with Intel for processors to power the cars.

Microsoft

Baidu driverless cars in test run during the 3rd World Internet Conference (WIC) on November 17, 2016 in Jiaxing, Zhejiang Province of China. VCG | Getty Images

Microsoft has a number of partnerships with automakers developing internet-connected and autonomous vehicles including BMW, Ford, Renault-Nissan, Toyota and Volvo. But its most intriguing deal in this new market is with the Chinese internet company Baidu. Baidu is developing an open source platform that it hopes will become the "Android" of self-driving cars, dubbed Apollo. Microsoft joined Baidu's Apollo "alliance," gaining a channel for sales of Azure cloud services to companies that use Apollo to build and run their self-driving cars. That deal only applies to companies using Apollo outside of China. Additionally, Microsoft has partnered with and provides Azure cloud services to Ola, Uber's competitor in India, which is expected to offer self-driving vehicles on its app eventually.

Amazon

Getty Images

Amazon's efforts in autonomous transportation appear most focused on getting items to consumers as quickly and efficiently as possible. At CES, Amazon was part of a Toyota announcement evealing a self-driving food delivery vehicle called the e-Pallette, just a concept car for now. According to NBC News, Tim Collins, a vice president for Amazon Logistics, said that the partnership with Toyota allows Amazon to "collaborate and explore new opportunities to improve the speed and quality of delivery for our customers." The Wall Street Journal reported in April that Amazon has cobbled together a team of about a dozen people to work on driverless vehicles for delivery. And in January, Recode reported on a patent that was awarded to Amazon for autonomous cars navigating reversible lanes.

Facebook

Sheryl Sandberg speaks about overcoming grief and resilience at the Commonwealth Club in San Francisco.

Chief Operating Officer Sheryl Sandberg traveled to Germany in September to address the prestigious Frankfurt Motor Show, attended by Chancellor Angela Merkel. "We're the only company in Silicon Valley that's not building a car," she quipped. Among the big five tech companies, Facebook has perhaps the smallest role in the car itself, but Sandberg was in Frankfurt to talk about its sponsorship of a "new mobility world," tying together the auto and tech industry. Facebook's research in virtual and augmented reality will potentially be used to give consumers a feel for the autonomous driving experience. It's all pretty vague right now.

Intel

A still image from a Mobileye video. Source: Mobileye

The chipmaker wants to become one of the world's biggest automotive suppliers. To that end, it acquired Mobileye for around $15.3 billion last year and partnered with Waymo to provide sensors and connectivity. Mobileye, out of Israel, makes systems used for collision detection and other features in self-driving vehicles. Intel made a number of self-driving vehicle announcements at CES. It revealed that BMW, Nissan and Volkswagen all plan to use Mobileye technology to create "high-definition maps" that enable self-driving cars to get around safely. The company is building a test fleet of 100 cars and showed off one of them at the show. The cars are equipped with twelve cameras, radar and laser scanners, and other chips, processors and systems developed by Intel and Mobileye.

Oracle

Larry Ellison, chairman of Oracle Corp., speaks during the Oracle OpenWorld 2016 conference in San Francisco, on Sunday, Sept. 18, 2016. David Paul Morris | Bloomberg | Getty Images

Finding a role for Oracle in the self-driving revolution will be quite a stretch. The closest thing we've heard so far is co-founder and Chairman Larry Ellison refer to a "self-driving database." In a September earnings call with analysts, Ellison compared the database of the future with the car of the future. "Self-driving cars eliminate the labor cost of driving, plus the high cost associated with human driving errors," he said. "Self-driving database eliminates the labor cost of tuning, managing, and upgrading the database, thus avoiding all of the costly downtime associated with human error." In other words, don't expect Oracle to drive you to and from work.

Cisco

Mack Hogan | CNBC

On Tuesday at CES, Cisco said it will bring superfast networking capabilities to Hyundai vehicles in 2019. If it works, Cisco's technology will help Hyundai use more sensors and process more data in their cars, taking them from semi- to fully autonomous. It will also allow Hyundai to deliver more "over-the-air" software upgrades to customers and enable vehicles to communicate with smart parking meters, toll gates and traffic lights. The companies said the tech will be included in Hyundai's 2019 premium lineup, though they didn't specify which models.

IBM

Attendees visit the Watson display that the 2015 Berkshire Hathaway Annual Shareholder's Meeting in Omaha, Nebraska on May 2, 2015. Lacy O'Toole | CNBC

IBM received a patent in March for a "machine learning system that can dynamically shift control of an autonomous vehicle between a human driver and a vehicle control processor in the event of a potential emergency." The company has multiple patents that tie together machine learning and driving. Whatever road technology we see from IBM will likely be connected to its AI engine Watson, which in 2016 worked with Local Motors on self-driving shuttle Olli.

Nvidia

Jensen Huang, CEO of Nvidia Rick Wilking | Reuters

Nvidia and competitors AMD, Intel and Qualcomm all unveiled new chip technology at CES this week. But Nvidia's was most focused on the emerging market for self-driving cars, even as the company maintains a stronghold in gaming. Nvidia's Xavier chipset, first revealed in 2017, is now being manufactured and will ship to select automotive customers and partners this quarter, the company announced. Dozens of companies have already been using it to test their fleets of "robo-taxis," the company has said. CEO Jensen Huang spoke at a Sunday press conference, boasting that it cost $2 billion and thousands of engineers to develop Xavier, a chipset that can supposedly conduct 20 trillion deep learning operations per second with very low power consumption. On the software side, Nvidia said that its Drive IX and Drive AR software development kits are being used to create undisclosed features (facial recognition or autopilot perhaps) for Volkswagen electric buses. Nvidia is also working with Uber, Baidu, and a start-up called Aurora on driverless cars.

Texas Instruments

A Texas Instruments Inc. TI-84 Tim Boyle | Bloomberg | Getty Images

Radars and sensors will be key parts of an autonomous car's hardware, and Texas Instruments is making a bid to be an integral part of the system. Last year the company introduced a portfolio of chips that includes sensors for driver assist and autonomous driving.

Qualcomm

Qualcomm CEO Steve Mollenkopf speaks during a keynote address at CES 2017 on January 6, 2017 in Las Vegas. Getty Images