Six years, four months, and six days. That's how long we have until 2030 arrives. The way time flies, it will be here before we know it.

A lot can change between now and then. In particular, I expect significant advances in artificial intelligence (AI). Which AI stocks will be the biggest in 2030? My prediction is that these three will rank at the top.

1. Apple

Apple (AAPL -0.35%) is the biggest company in the world today based on market cap. I suspect it'll be the biggest in 2030 as well. And I think that the tech giant's AI efforts will play a key role in holding onto the No. 1 spot.

To be sure, Apple hasn't been at the center of the AI frenzy this year as much as others have. Its Siri AI-powered assistant almost seems antiquated in light of the generative AI explosion ignited by OpenAI's ChatGPT.

Don't underestimate Apple, though. The company invests heavily in AI development. CEO Tim Cook mentioned in the second-quarter conference call that Apple has conducted research and development in generative AI and other AI technologies for years. He stated, "[W]e view AI and machine learning as core fundamental technologies that are integral to virtually every product that we build." 

I predict that Apple's devices will be the top means of delivering AI to end users through the rest of the decade and beyond. I also think that the company has tremendous opportunities in spatial computing -- the interaction between technology and the physical world.

2. Microsoft

Only one AI stock other than Apple has a market cap of over $2 trillion. It's Microsoft (MSFT 1.82%). My hunch is that the Seattle-based company will remain the No. 2 AI stock in 2030.

Unlike Apple, Microsoft has been in the AI spotlight in a huge way this year. The company pulled off what I view as an exceptionally astute move by teaming up with (and investing billions of dollars in) OpenAI.

Microsoft should be able to win on multiple AI fronts. Its productivity software can help users be even more productive thanks to AI. Microsoft's software development platform should enable programmers to develop code more quickly. I fully expect the momentum of the company's Azure cloud platform to accelerate as well thanks to its AI tools.

AI should also benefit Microsoft in its own internal development efforts. That could especially be helpful in the gaming arena with the pending acquisition of Activision Blizzard looking more likely to close.

3. Alphabet

Some might be surprised that I'm predicting Alphabet (GOOG 9.96%) (GOOGL 10.22%) will be the third-largest AI stock in 2030. There is a theory that AI could instead disrupt Alphabet's Google Search business, which currently generates most of the company's revenue.

I'm not convinced that's going to happen. Alphabet has done a good job, in my opinion, with its early integration of generative AI with Google Search. So far, the company's search revenue is holding up quite well despite the popularity of ChatGPT and other large language models (as evidenced by its impressive stock performance thus far this year).

My view is that it's more likely that AI provides a significant long-term tailwind for Alphabet. Its Google Cloud business should attract more customers as they scramble to take advantage of AI. Self-driving car technology unit Waymo has a tremendous opportunity. AI is already helping Alphabet boost its advertising revenue and will probably continue to do so.

I also think that Alphabet's quantum computing expertise could be a major wild card. The company has achieved several important milestones in the field. It's possible that by 2030, quantum computing could be an emerging growth driver for Alphabet.

How my prediction could flop

Would it be shocking to me if my prediction didn't come true? Not really. 

For example, I could see Microsoft potentially picking up more steam and vaulting ahead of Apple. Perhaps instead Alphabet will unleash its AI dragons within the next few years in a game-changing way and move higher in the ranking. Maybe I'll be proven wrong about AI disrupting Google Search.

There are also a few other AI stocks that could gain ground in a major way. Amazon runs the biggest cloud services platform and could be a huge AI winner. Maybe Nvidia's jaw-dropping growth trajectory will continue for years to come. Cathie Wood's projections about the robotaxi market might be right, resulting in Tesla leaping ahead of the rest of the pack.

For now, though, I like the chances for Apple, Microsoft, and Alphabet. We'll know in six years, four months, and six days if I'm right.