After a period of uncertainty, confidence has returned to the market and sent stock prices soaring. This raises the question, have stocks soared too high?

Not according to Goldman Sachs’ Silvia Ardagna. The economist believes that while the global economy might be slowing down, the US economy is stronger than most other regions and there is yet more fuel left in the tank to propel it forward.

“The de-escalation of trade tensions between the U.S. and China has triggered the question whether investors have been too negative and there could be some positive surprises,” said Ardagna, adding, “The main returns in our view still come from having an overweight to U.S. equities.”

There’s no one true strategy to guarantee making money in the investment markets, but finding a stock a with strong upside potential is a good beginning. Today, we’ve used TipRanks’ Stock Screener to find three Strong Buys with buy-side potential over 40%. They come from a range of sectors – education, biopharmaceuticals, technology – and only two are showing positive performance so far this year. But all have attracted serious attention from high-rated analysts, who have seen clear paths toward high profitability for each of them.

Aspen Group (ASPU)

Starting in the education-tech field, Aspen Group operates two private, for-profit universities, the United States University based in San Diego and the distance-learning Aspen University. Both are accredited colleges and offer a variety of undergrad and post-graduate courses and programs.

Education is an in-demand field, and Aspen’s Q1 fiscal 2020 earnings reflect that demand. Student enrollment was up 46% year-over-year, with 1,929 new enrollments, and revenues were up 43% to $10.4 million – a record for the company. CEO Michael Matthews noted a key point in the earnings: “Fiscal 2020 is off to a strong start with record revenue and enrollments in our seasonally weakest summer quarter.”

After difficult stock performance through the summer, ASPU shares took off at the end of August, and the stock is up 21.5% year-to-date.

Northland analyst Michael Grondahl notes an important point that is easily overlooked: Both of Aspen’s universities offer degrees and accreditation programs in nursing, a field in high demand. In his initiation-of-coverage report, Grondahl says of ASPU generally, “We believe Aspen Group represents a compelling opportunity as a higher-education provider that makes obtaining a degree more affordable and cost-worthy for students. ASPU has seen consistent enrollment growth, with total enrollment at just under 10,000 students.” His $10 price target suggests an impressive 50% upside potential for the stock. (To watch Grondahl's track record, click here)

Aspen sells for a bargain $6.66, a price that is especially attractive when the upside potential is taken into account. The average price target, $9.75, indicates room for 46% growth to the upside in this stock. The Strong Buy analyst consensus is based on 4 Buy ratings set in the last two months. (See Aspen stock analysis on TipRanks)

Sarepta Therapeutics (SRPT)

Based in Cambridge, Massachusetts, Sarepta is a mid-cap ($7 billion) biotech company focusing on treatments for genetic disorders. The company’s first approved product, Exondys 51, is a treatment for Duchenne muscular dystrophy, and is approved for patients with a confirmed mutation in the DMD gene. Sarepta has 16 additional projects in the pipeline, mostly targeting forms of muscular dystrophy, and is a collaborator on 9 others.

Unfortunately, Sarepta received devastating news in August. The FDA rejected the company's NDA application for golodirsen (SRP-4053) for the treatment of boys with Duchenne muscular dystrophy (DMD) amenable to exon 53 skipping. The CRL, which is the FDA's euphemism for a rejection, outlined two main concerns: Intravenous (IV) infusion ports at risk of infections, and preclinical models of golodirsen displaying renal toxicity, observed following administration of other antisense oligonucleotides. Disappointed investors expecting the company to announce FDA approval pounded the stock all the way to a 52-week low of $72.05 in late September.

However, SRPT has shown head-turning signs of life recently. Over the past five weeks, Sarepta stock has rallied about 30%, and Guggenheim analyst Whitney Ijem sees much more upside potential.

Ijem gives an upbeat description of the company’s current standing in a November 1 initiation report: “We like the company's strategic positioning in DMD given its base RNA platform and leading gene therapy. Despite recent controversy on both, we expect positive progress in the next 6-12mos that should drive shares higher. Beyond DMD, the company has built an impressive pipeline of gene therapies in other neuromuscular diseases… we think current levels provide a highly favorable entry point ahead of what we expect will be a productive 2020.” Ijem’s $183 price target suggests a most impressive 94% upside to SRPT. (To watch Ijem's track record, click here)

Indeed, the company’s robust pipeline, with 9 products in clinical testing and one Exondys 51 in commercial trials, shows that SRPT’s expenditures are going to a good end. Investors are willing to be patient with a biotech that has a strong research program.

All in all, Sarepta has 18 buy ratings in the last three months, against a single hold – a clear sign that analysts and investors both are impressed with the company’s potential. Shares sell for $94, and the average price target of $191 gives the stock an eye-opening 101% upside. (See Sarepta's price targets and analyst ratings on TipRanks).

Zix Corporation (ZIXI)

In Zix, we move into the technology sector. This small tech company has a market cap of just $395 million, but a secure niche in the email security sector, providing encryption, data loss prevention, and mobile applications. Zix boasts over 80,000 customers, and bases its business on the popular – and profitable – cloud-based SaaS model. At the turn of the year, Zix made a significant acquisition when it bought AppRiver, a provider of cloud-based cyber security and productivity services.

In Q3, reported at the end of October, ZIXI met the Street’s expectations with a 13 cent EPS. This was a 44% year-over-year gain. In terms of revenues, ZIXI beat the estimates by 1.16%, posting $47.83 million for the quarter. This was an impressive 168% increase from the year-ago quarter’s revenue figures. As fits a company with a healthy earnings profile, ZIXI shares are up 24% year-to-date, matching the performance of the S&P 500 index.

Daniel Ives, 4-star analyst from Wedbush, initiated coverage on the stock last week, writing of the company, “Zix is a leader in the email encryption and delivery market providing security solutions to over 80,000 customers mainly focused on compliance driven industries such as Financial Services, Healthcare and Government. Email encryption accounts for almost 90% of its total revenue and today’s BYOD world presents many new security threats and challenges as we believe the company has strong differentiation from its competition [...] We believe that the Street does not currently fully appreciate the full potential of the AppRiver acquisition to drive top-line growth as well as EBITDA margin expansion.”

Ives suggests that if everything goes as planned, ZIXI will be a $10 stock in the next 12 months, implying about 40% return. (To watch Ives' track record, click here)

All in all, at just $7.10, ZIXI shares are another bargain for return-minded investors. The stock’s $10.33 average price target implies an excellent upside of 44%, and while the analyst consensus of Strong Buy is based on just three ratings, all three were given in the past two weeks. Clearly, this is a stock that is starting to attract attention from Wall Street’s analysts. (Get TipRanks' free stock analysis report on ZIXI)