With the exception of a few minor hiccups, the stock market has been practically unstoppable since hitting its lows in March 2009. The broad-based S&P 500 is up by more than 250%, while the Dow Jones Industrial Average has rallied about 215% from its lows.

With such strong returns, it's not surprising to find that companies of all sizes (small, medium, and large) and asset classes (value, blend, and growth) have excelled, based on data aggregated from J.P. Morgan Asset Management.

A magnifying glass highlighting market data in a financial newspaper.

Image source: Getty Images.

In fact, according to recent data from FactSet Data Systems, the S&P 500's forward P/E is at its highest value in well over a decade. This implies that investors are fully expecting a strengthening U.S. economy, and that they're willing to pay more for stocks of all sizes and asset classes.

These two assets classes could be set to outperform

However, after reviewing J.P. Morgan Asset Management's end-of-year data from 2016, a pretty stark contrast stands out. Have a look below at the comparison of the current P/E of stocks, based on their size and asset class, relative to their 15-year average P/E and you'll see what I mean:

  Value Blend Growth
Large 117.5% 110.3% 103.1%
Mid 115.7% 110.4% 102.3%
Small 118.5% 117.4% 114.8%

Data source: J.P. Morgan Asset Management. Table by author. 

You'll note that while all companies and asset classes are, in aggregate, being valued above their 15-year average P/E ratio (since all figures are above 100%), large-cap growth stocks (103.1%) and mid-cap growth stocks (102.3%) are lagging a bit. This could imply that both of these asset classes are ripe to outperform in the years ahead. 

Growth stocks already have a natural advantage with the Federal Reserve remaining cautious in its monetary tightening cycle. The perpetuation of low lending rates is an important cog that fuels growth companies by encouraging them to borrow money at a relatively low cost in order to hire, reinvest in their business, and expand. Even with three Federal Reserve rate hikes since Dec. 2015, the federal funds target rate is still an exceptionally low 0.75% to 1%, which is quite conducive to borrowing. In other words, large- and midcap growth stocks could still be primed to outperform.

Here are a few companies you may want to keep your eyes on.

An investor circling stocks to watch in a newspaper.

Image source: Getty Images.

Large-cap growth stocks worth eyeing

According to the data, large-cap growth stocks (traditionally defined as having a market cap of $10 billion or larger, with a growth rate of 10% or more per year) currently have a P/E of 18.1 compared to a 15-year average P/E of 17.6.

Take a company like Celgene (CELG) as a good example. On the surface, its trailing P/E of 50 seems terrifying. However, it's capable of growing its revenue by a double-digit percentage through the remainder of the decade (and beyond), and is valued at just 14 times its 2018 profit projections, which is well below the current P/E average of 18.1 for large-cap growth stocks.

Multiple myeloma drug Revlimid is Celgene's bread and butter. Sales of the drug continue to grow by 15% to 20% annually as multiple myeloma diagnoses grow, duration of use improves, pricing power rises, and new label expansion opportunities arise. Celgene also worked out a deal with generic drug developers to keep most generic Revlimid off the market until Jan. 2026, giving Celgene a clear runway to be a biotech cash cow for a decade to come.

A person selected a reaction from a Facebook post.

Image source: Facebook.

Another benefactor could be Facebook (META -1.65%), which at a valuation north of $400 billion might still be significantly undervalued based on its growth potential. The social media giant's 12-month trailing P/E of 40 might seem unsightly, but its forward P/E of just 20 and PEG ratio of 1.1 makes it look a whole lot better.

And I know what you're probably thinking: "A P/E of 20 is still higher than the current 18.1 P/E for large-cap growth stocks. While that's true, Facebook has also annihilated Wall Street's EPS consensus by at least 10% in four of the past five quarters. This suggests Facebook's actual forward P/E might be closer to 18 if it keeps trouncing projections.

Facebook's success relies on its ability to engage consumers, as well as the fact that it's yet to monetize a number of its key platforms, including Messenger and WhatsApp. With a veritable smorgasbord of revenue potential in the years to come, Facebook may be worth a closer look.

An investor giving the thumbs-up sign next to a rising stack of gold coins.

Image source: Getty Images.

Mid-cap growth stocks you'll want to know

The data also shows mid-cap growth stocks ($2 billion to $10 billion market cap) valued at a current P/E of 19.5, which is only slightly ahead of the 15-year average of 19.1.

One potentially attractive company in this asset class is gold-mining company Yamana Gold (AUY), which is set to benefit from a number of projects transitioning into commercial production in 2018 and 2019. It could make the company's forward P/E of 16 look exceptionally enticing.

Both its Cerro Moro and C1 Santa Luz mines are expected to begin commercial production next year. C1 Santa Luz, after an initial 130,000 ounces of gold in its first year, is expected to settle into an average of 114,000 ounces of gold production in its first seven years. Cerro Moro is projected to deliver an average of 130,000 ounces of gold per year. Plus, the Chapada mine will add 45,000 to 60,000 ounces of gold for a four-to-five-year period beginning in 2019, and the recently acquired Riacho dos Machados mine will have ramped up production to 100,000 ounces of gold per year.

An airplane on the runway.

Image source: Pixabay.

Another great example of a possible outperformer is aircraft leasing company Air Lease (AL 0.10%), which is valued at less than 10 times Wall Street's profit projections for 2018.

Air Lease's business model is exceptionally simple and extremely profitable. Because aircraft are so expensive for airlines to buy, Air Lease negotiates long-term leases with airlines that are looking to boost capacity and/or improve fuel efficiency without the high costs and waiting associated with purchasing new planes. As of the end of 2016, Air Lease's portfolio consisted of aircraft that averaged only 3.8 years in age, but had an average lease term on remaining deals of 6.9 years. This means very predictable cash flow. Plus, Air Lease can monetize its portfolio by selling older aircraft, thus refilling its pockets for a new round of aircraft purchases.

Just because the stock market has had a strong run higher doesn't mean these growth stocks can't still outperform.