One of the best ways to find great investment opportunities is to go off the beaten path. Bitauto.com (NYSE:BITA), Caesarstone (NASDAQ:CSTE), and Omeros Corporation (NASDAQ:OMER) don't get a lot of attention from Wall Street, but they might be worthy of a place in your portfolio. Here's what three of our contributors think about these underfollowed companies.

A Chinese company under the radar

Brian Stoffel (Bitauto): Wall Street has a simple way of signaling that it wants the world to know about a stock: analysts initiate coverage on it, and ask questions on the company's quarterly conference call. Currently, only four analysts cover Chinese auto e-commerce player Bitauto.com, and the same number participated in the latest conference call.

Investors looking for a unique international growth story, however, should check out the $2 billion company. It got its start by creating a platform to connect auto dealers with auto buyers in China via the internet. Specifically, it offered up advertising, digital marketing, and subscription services that allowed sellers to create virtual showrooms.

For much of the company's history, this was its bread and butter. And indeed, it has attracted over 25,000 subscriptions.

But it is the recent addition of transaction services that has me excited. The platform connects consumers with auto finance companies, banks, and insurance providers to make the car-buying experience as seamless as possible. If you look at results over the past two years, you'll see how much growth this division has experienced.

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As a shareholder, I'm excited by the prospects, but there's still risk involved with the stock -- the state of the Chinese economy looms large, competition exists, and autonomous driving could drive down demand for cars -- there's clearly a pathway for growth at the company I think Wall Street might be missing.

A countertop manufacturer

Tim Green (Caesarstone): Small companies in unexciting industries often don't get much attention from Wall Street. Caesarstone, a manufacturer of quartz surfaces used in kitchen countertops and other applications, is scarcely followed by analysts, and it's likely you've never heard of the company. But the stock should definitely be on your radar.

A Caesarstone countertop.

Image source: Caesarstone.

After some temporary issues in its U.S. business were resolved, Caesarstone put up some solid numbers during the first quarter. Total revenue grew by 16.7% year over year, with U.S. revenue surging 17.7%. Net income was down slightly, due in part to increased investments in marketing and sales, but the company expects this spending to drive revenue growth of around 9% in 2017.

The investment thesis for Caesarstone is simple: Quartz represented just 16% of the $95 billion global countertop market in 2016, and just 14% of the U.S. market by volume. Quartz is the fastest-growing category, and Caesarstone expects it to continue to displace other materials like granite and laminate going forward.

Caesarstone stock trades for a little over 16 times adjusted earnings per share. With many years of growth likely ahead as quartz becomes more popular, now is a good time to pick up some shares.

The best biotech stock you've never heard of

Cory Renauer (Omeros Corporation): With a tiny little market cap of $681 million, odds are good that you've never heard of this stock. In a few more years, though, I think you'll wish you had. Sales of its first approved product are soaring, and another drug in late clinical-stage development could rise even further.

Although it seems like Wall Street wants to keep this gem under wraps, its lead drug is becoming awfully popular among ophthalmologists. In early 2015, Omidria became the first drug approved by the Food and Drug Administration to keep pupils dilated during cataract removals and lens replacement surgeries. In the first quarter this year, Omidria sales jumped 69% higher than during the same period last year.

Omidria finished the first quarter on pace to reach $49.2 million in sales this year, but it's only scratched the surface of an enormous market. In the U.S. alone, eye surgeons perform millions of procedures each year that might run a bit smoother with the use of Omidria, and I wouldn't be surprised if annual sales of the drug rise to several times their current level.

While Omidria alone makes Omeros Corporation look like a buy at recent levels, the company has a rare-disease candidate in late-stage clinical trials that could be worth much more. The stock has surged recently in response to encouraging data for OMS721, which suggests it also has a shot at crossing the $1 billion threshold.

Biotechs tend to trade at multiples several times higher than their annual sales, which gives this hidden gem multibagger potential. Of course, Omidria needs to continue along its current trajectory, and OMS721 has to eventually earn key FDA approvals. Watching the Omeros Corporation story unfold will be exciting, but don't expect Wall Street to provide the play-by-play.

Brian Stoffel owns shares of Bitauto Holdings and Bitauto Holdings. Cory Renauer has no position in any stocks mentioned. Timothy Green owns shares of Caesarstone. The Motley Fool recommends Caesarstone. The Motley Fool has a disclosure policy.