Congratulations! You've survived another summer. The kids are heading back to class, and the grown-ups have a couple of months to catch our collective breath before the madness of the holidays starts. One aspect of your life that you may have neglected this summer? Your investment portfolio. If that's the case, there's no time like the present to get back in the swing and find some top stocks to help you reach your financial goals.

To help you get started, we asked five of our top contributors to put their best ideas forward, and they came up with a powerful collection of companies: leading online stylist and apparel retailer Stitch Fix (SFIX -4.72%), specialized software maker Autodesk (ADSK 0.78%), underappreciated mall owner Simon Property Group (SPG -0.41%), amazing turnaround Lululemon Athletica (LULU 1.87%), and tiny -- but fast-growing -- engineering company NV5 Global (NVEE -1.34%).

Stopwatch with the words time to buy printed on the face.

Image source: Getty Images.

Keep reading to learn why our contributors each tapped one of these stocks as their pick for a top stock to buy in September.

A long-term apparel play

Jeremy Bowman (Stitch Fix): As an investor, there's nothing I like more than when a growth stock goes on sale. That's exactly what's happening right now with Stitch Fix, the customized, on-demand styling service that is disrupting the $342 billion U.S. apparel market.

Since its recent peak on July 1, the stock has fallen about 40% even though there's been little direct cause for that slide. Instead, investors seem to have fled because of the same fears that have dogged the stock since its 2017 IPO: the simmering trade war with China and Amazon's interest in the customized clothing space.

Both of these threats seem overblown. A trade war with China and the tariffs that would come with it could actually help Stitch Fix. Much of the U.S. apparel retail industry is already struggling, getting pressured by growing e-commerce companies like Amazon and Stitch Fix, and has found itself with an excess of stores. Therefore, tariffs are more likely to have a damaging impact on Stitch Fix's bloated competitors than on Stitch Fix itself. A full-on trade war could help drive a number of Stitch Fix's competitors out of business.

In the case of Amazon, the e-commerce giant has loomed as a threat to Stitch Fix for a while with programs like Prime Wardrobe, and it just launched its own copycat styling service. However, apparel has proven to be a challenging business for Amazon, because the highly fragmented industry requires the sort of soft touches and skills that have often been a weak spot for the algorithmically driven tech giant. In addition, Stitch Fix has a near-10-year head start over Amazon with its own styling service, and other competitors' struggles show that this is a difficult business to get right.

The long-term case for Stitch Fix is self-evident. The company is primed to benefit from two huge secular tailwinds in its industry: e-commerce and personalization. It's the leader in its category. It's profitable and has been for several years, and management is targeting 20% to 25% revenue growth over the long term.

However, now looks like an especially good time to pick up Stitch Fix shares, since in addition to its bargain price, there are a number of positive catalysts coming up that should help boost its next round of results and long-term growth.

First, we're in the thick of the back-to-school shopping season. Stitch Fix launched its bid for the kids' apparel market last July in time for the 2018 back-to-school season, but with a another whole year to build awareness for the new segment and to expand its product selection, it's a good bet that Stitch Fix Kids will see significant growth this quarter. The bankruptcy of Gymboree earlier this year, a leading kids' apparel retailer, can't hurt either.

Stitch Fix U.K., its first foray into the international market, which launched in May, represents another significant growth avenue. The U.K. seems especially promising for Stitch Fix because online apparel shopping is already substantially more popular there than it is in the U.S., and CEO Katrina Lake has said in a previous earnings call that the company's personalization model will make it more differentiated in the U.K. than it is in its home market.

Stitch Fix shares surged 15% on the company's most recent earnings report in June when it posted 29% revenue growth, showing that the popular short play -- 33% of its float is sold short -- is being underestimated.

The company's fourth-quarter earnings report is due out on Oct. 1. Analysts are expecting revenue to jump 35.9% to $432.5 million with a boost from the U.K. launch but to see earnings per share fall from $0.18 to $0.04.

With the stock sell-off over the last couple of months, a promising setup for a short squeeze, and an earnings report on deck that's expected to show strong growth following expansion with the kids' line and the U.K., there's a reasonable possibility that Stitch Fix shares could surge by 50% or more over the next month.

Predictable demand

Brian Feroldi (Autodesk): One of the most challenging aspects of investing is finding businesses that can grow at a predictable rate for years on end. That's not easy to do in today's hypercompetitive marketplace, but I'm confident that Autodesk is up to the task.

Autodesk is a software company that makes products for the architecture, engineering, construction, manufacturing, media, education, and entertainment industries. It is best known as the maker of AutoCAD, which is a 2D and 3D computer-aided drafting program that enables users to create highly detailed blueprints and engineering plans. But Autodesk also sells dozens of other leading products that include Revit, Maya, Fusion 360, BIM 360, and more.

Autodesk sold its software by using a licensing model for decades, but a few years ago, it made the switch to a software-as-a-service model. That was a painful transition in the short term -- revenue, profits, and free cash flow all dropped immediately -- but the company is now reaping the rewards from the business-model change. The vast majority of the company's revenue is now recurring and growing fast, its gross margin is high and climbing, and the company is starting to crank out adjusted profits and free cash flow.

What's so exciting about the "new" Autodesk is that its high growth rates look as if they are here to stay for at least two reasons.

First, the company's existing customers find the software to be so useful that they tend to spend more on Autodesk's products each year. Last quarter, management stated that its net revenue retention range -- which measures existing customer spending from period to period -- landed within management's target range of 110% to 120%. This means that the company is able to grow its revenue by at least 10% without adding a single new paying customer.

Second, a huge number of legacy customers haven't upgraded to the company's subscription model yet. Autodesk believes that more than 18 million people use its software on a regular basis, but only about 4.3 million of them have made the switch. This means that about 13 million users are actively using Autodesk's legacy products that were purchased under the licensing model years ago. Management is actively working to convince this group to upgrade to the subscription software by sending out constant upgrade reminders and rolling out new features that make the software more useful (such as offering augmented reality and virtual reality features). The company should be able to convince the majority of them to make the switch over time.

With all these factors added together, Autodesk looks poised to grow its top line at a strong rate for years to come. When factoring in steady margin improvements, operating leverage should help to grow the bottom line even faster (Wall Street currently expects 86% annualized profit growth over the next five years).

Autodesk's stock isn't particularly cheap right now -- shares trade for more than 11 times sales and 30 times next year's earnings estimates -- but I've learned that it is almost always worthwhile to pay a premium to own a high-quality business. That's why I recently added a few shares of this high-growth stock to my portfolio and would suggest that you do the same.

A mall operator that's on another level

Matt Frankel, CFP (Simon Property Group): When it comes to retail stocks, there are many that I would stay away from. A wave of store closures and retail bankruptcies has swept through the industry, and it's likely not done just yet.

However, when it comes to mall and shopping center owners, Simon Property Group is simply in a league of its own. This real estate investment trust, or REIT, is one of the largest owners of real estate of any kind in the U.S. and doesn't deserve to be put in the same category as the rest of its industry.

Simon owns a large portfolio of upscale malls and outlet properties. Many of Simon's malls are among the most valuable retail properties in the world -- particularly those that are operated under the company's Mills brand. Simon also has a dominant market share in the outlet industry. There are eight major outlet mall operators in the U.S., and Simon owns about twice as much square footage as the other seven combined.

This scale gives Simon some tremendous advantages. For one thing, it has tons of capital to invest in its properties to keep them a step ahead of competitors and, more importantly, to do battle with e-commerce and win. Simon's malls have been destinations for some time, but in recent years, Simon has been investing heavily to add mixed-use elements to its properties. For example, at many of Simon's properties, you'll find hotels, co-working space, apartments, casinos, entertainment venues, and other nonretail elements. Simon is also investing in many up-and-coming trends, such as esports, in order to keep its properties as current as possible.

This not only creates a portion of Simon's revenue that is virtually immune to e-commerce and other retail-sector headwinds but also creates a built-in source of foot traffic for Simon's retail tenants. In fact, Simon's malls have been so successful in bringing shoppers in the door that many retailers who have been traditionally online only have started opening up stores in Simon's malls (Untuckit, for example). And Simon's retail tenants have reported average sales per square foot growth of 3.5%, not a decline.

One thing that may sound alarming at first is that Simon has a fair amount of space that is occupied by struggling department stores. The 65 remaining J.C. Penney stores and 25 remaining Sears locations in Simon's malls account for more than 8% of the company's total square footage. And although I wouldn't put it in the same boat as those other two, Macy's accounts for another 12%.

However, Simon sees this as one of its biggest opportunities. By redeveloping these existing spaces as they become vacant into mixed-use elements, Simon can add valuable features to its malls at a substantially lower cost than building them from the ground up.

Because of the retail headwinds and recession fears in the market, Simon is trading for just greater than its 52-week low and sports a well-covered 5.7% dividend yield. Now could be a great time to add this mall operator with tremendous competitive advantages to your portfolio at a big discount.

Strike a pose

Dan Caplinger (Lululemon): Many successful companies often fall prey to a single error that destroys their businesses. Lululemon Athletica made such a mistake several years ago, and it came within a hair's breadth of going from a promising high-growth leader in the athletic apparel industry to another story of unfortunate failure. Yet unlike so many of its peers in the retail industry, Lululemon managed to mount a full recovery, and those investors who stayed the course along the way have benefited greatly from the yoga apparel company's subsequent rise back into the top echelons of the athletic apparel space.

Lululemon's problems stemmed from a quality-control issue in 2013 that threatened the entire basis for the yoga apparel company's business model. At the time, Lululemon was becoming famous for its premium yoga wear and accessories, and its customers were willing to pay up for the company's products because of their status and their high quality. Efforts from Lululemon to connect with instructors at key yoga studios across North America also contributed to the company's brand awareness and built up sales.

Yet complaints that some of its yoga pants were sheer enough to see through led some customers to conclude that Lululemon might be skimping on the materials that had originally earned it its strong reputation. Moreover, the yoga apparel company's CEO failed to deal with the situation quickly and efficiently, instead improperly deflecting blame onto some of Lululemon's own customers. That misstep created an even bigger uprising.

In the end, though, Lululemon found a way out of its bind. Replacing its CEO was an important first step toward regaining customer confidence in the company, and Lululemon worked hard to ensure that quality-control issues wouldn't repeat. Even with all that work, it took several years for the retailer to return to its former growth trajectory.

Now, things have never looked better for Lululemon. In its most recent quarter, Lululemon posted 20% year-over-year growth in revenue, helping to boost net income by nearly 30% from the previous year's period. Comparable sales are rising at double-digit-percentage rates, and cost management has helped Lululemon boost its margin figures as well. Customers can now find more Lululemon store locations than ever, as the retail chain has returned to expansion mode.

Lululemon is scheduled to give a quarterly report in early September, and investors are enthusiastic that the yoga apparel specialist will be able to continue to grow. With strategic moves to go beyond its core market to attract a greater swath of yoga enthusiasts, Lululemon thinks it can produce considerable growth. Moreover, as athletic apparel becomes more widely accepted as casual wear for all occasions, the strong reputation that Lululemon has rebuilt should be an even greater asset.

Long-time investors in Lululemon have already reaped a lot of success from the yoga product retailer, but the company has a lot more potential growth ahead of it. Now's a smart time to take a closer look at how Lululemon could overcome the headwinds that many retailers in other niches have faced and continue to produce strong returns for shareholders.

Buy on cyclical fears; hold for decades of growth

Jason Hall (NV5 Global): This small infrastructure engineering and consulting company has seen its stock price fall sharply; it's down 27% over the past few months, and even after a strong recovery earlier this year, the stock price is still 32% below the all-time high, reached about one year ago.

Why has NV5's stock fallen so far so quickly? In short, because the infrastructure projects it consults on are complex, expensive, and funded by either government spending or capital investments from cyclical industries. And with so much concern about the state of the global economy and real fears of recession, investors are eschewing companies viewed has having big cyclical exposure and prioritizing "safer" investments.

For investors who are smart enough to look beyond next quarter or even the next year, that's created an excellent opportunity to buy. In short, NV5 is primed for many years of growth to come. There's an immense need for infrastructure on a global basis: By 2040, almost $90 trillion will have to be spent to meet the world's infrastructure needs. This is a product of both global middle-class and urban population growth, as well as the need to modernize and improve infrastructure in the U.S. and Europe to remain competitive with the rest of the world.

So why NV5? Because it has an executive team with a great track record of success, including its CEO, who's also the founder and biggest shareholder, with about a 25% stake in the company.

But why now? you may ask. In short, because while I don't know any more than the next person when the next recession will happen -- nor what its impact on infrastructure spending will be -- I do know that NV5 continues to absolutely nail it and represents an incredible combination of value and growth at recent prices.

Through the first half of 2019, revenue is up 23%, adjusted earnings per share increased 17%, and operating cash flows surged 61%. Moreover, it's not just acquisitions driving growth; organic revenue increased 6% last quarter as the company continues to leverage its ability to provide multiple services to meet its clients' needs on big, complex projects.

Another example of how its strategy is paying off is in its backlog, which has increased 43% since last year and passed $450 million last quarter.

Moreover, management expects business to accelerate in the second half of the year, raising its full-year guidance and now calling for $535 million in revenue and earnings of $2.71 per share at the midpoint of guidance. That works out to 28% and 17% growth, respectively, and it trades for about 22 times that earnings guidance at recent prices.

Worried the stock price might fall even further from here? Maybe another 20% or 30%? Consider this: Shares have nearly doubled over the past three years and surged an incredible 554% over the past five years because the company continues to deliver incredible results, and that's after the 30% drop from last year's high. Better to buy the excellent business at a fair price than get caught on the sidelines trying to pay the perfect price.