At the beginning of 2012, I set out to form what I oh-so-modestly called "The World's Greatest Growth Portfolio." So far, the portfolio has lived up to its moniker, returning 28% for the year, and outperforming the S&P 500 by just under 10 percentage points.

The thesis for forming the portfolio was pretty simple: Invest first and foremost in companies that demonstrate exceptional levels of innovation, with special emphasis given to those that I believe will be around decades from now.

Yesterday, I revealed the four companies making up my core. Today, I'm revealing the four companies that will make up the Tier One companies of 2013's portfolio. These are companies that I'm almost certain will be around a decade from now, though I can't say with certainty that I know they'll be leading their industries when that time comes. Each of the companies will get a 7.5% allocation in the portfolio.

I've reviewed 18 different companies  for this portfolio, so without any further ado, here are the four that will be this year's Tier One stocks.

Apple (AAPL 0.51%)
Many people may wonder why, with the ridiculously low P/E of 12 and a history of innovation, I wouldn't make Apple a core holding.

I'll be clear: Apple is without a doubt the most impressive company of the past 20 years. However, what makes it so impressive -- creating products we didn't even know we ever needed -- is an almost magical quality. I'd love to believe that this magic will last forever, but I wouldn't be honest  if I thought that was a guaranteed thing.

At the same time, I certainly don't think the company is going to disappear overnight, and though the loss of Steve Jobs is a concern that I can only gauge over time, there's no denying he instilled a culture of innovation at the company. With the next iGadget likely around the corner, and a pretty cheap price tag right now, Apple's worth holding in the portfolio.

Intuitive Surgical (ISRG 0.71%)
There's no denying the innovation in this company's DNA. Intuitive's daVinci Robotic System was originally an idea the military had for remotely performing surgery on injured soldiers. When Dr. Frederic Moll decided it might have a peace-time application, he was on to something.

Currently, prostatectomies and hysterectomies make up the vast majority of surgical procedures performed robotically, but there is a lot of experimentation to see whether there could be other applications.

The reason Intuitive moved from the Core section of stocks to Tier One, however, simply has to do with very subtle trends that I sense on the macro level. Instead of treating cancer, I think there's a wise move toward prevention through healthy eating and lifestyles -- incidentally, that's why Whole Foods (WFM) remains a firm choice in my Core.

During the most recent earning call, CEO Dr. Gary Gunthart stated that the number of procedures performed came in lower than expected because of "change in treatment recommendations for low-risk cancer patients away from definitive treatment." To me, that's a risk worth taking note of.

Though it's no longer a Core stock, Intuitive certainly still deserves a place in the portfolio.

IPG Photonics (IPGP 0.98%)
IPG's story is simple. The company makes fiber-optic lasers that are cheaper, use less energy, and are more powerful than standard carbon-based lasers. The applications for these lasers are vast, from cutting and welding heavy machinery, to allowing the military to detonate explosives from a safe distance.

The company's stock has made great strides in 2012, going up 92%. But I think there's still a big market out there for this company.

Starbucks (SBUX 0.65%)
Finally, we have a company that wasn't even included in my 2012 portfolio but jumped all the way up to Tier One for 2013. It might seem like an odd move, but the more I thought about it, the more I realized that I want to invest in one of the country's most innovative leaders: Howard Schultz.

Though the company might have reached saturation in America, there's still a lot of opportunity abroad. And with the acquisitions of several different food and tea companies, I think Starbucks could be serving up just what the locals want in countries far from here.

An unusual approach?
As you might have noticed, I tend to focus a little less on numbers and a little more on intangibles when it comes to evaluating my investments. For some, that seems silly, but it's a strategy that has served me well and fits with my style.

If you'd like a more numbers-centric, detailed view of where Apple stands in the technology field, I highly suggest checking out our special premium report on the company.