Once-prosperous companies fall on hard times more often than one might think. Changing industry dynamics, excessive debt levels or poor management decisions can take even the largest of companies to a breaking point.

When bankruptcy fears set in, these stocks can sometimes fall into the low single-digits. Indeed, many of these stocks go bankrupt. However, some of these become “fixer upper” stocks, creating massive amounts of wealth for astute, patient investors.

Because they’ve faced hardships that weighed on their share prices, we define fixer uppers as stocks of $5 per share or less. Of course, buying a stock below $5 per share takes a great deal of courage. By making wise investments in troubled companies, however, even small investors can sometimes finish rich with fixer-upper stocks.

These four companies present possible opportunities for such outsized growth:

Fixer-Upper Stocks: AK Steel Holding Corporation (AKS)

AK Steel Holding Corporation (NYSE:AKS) struggled for years as competition from imports hampered profit growth. Now, with the “fair trade” policies of the Trump administration, opportunity has returned to the West Chester Township, Ohio-based steel company.

AKS stock experienced a massive selloff in 2008. In that time, the stock fell from a high of over $73 per share in May 2008 to a low of $5.39 per share by March 2009. The stock never recovered. Although it rose into to over $20 per share in 2010, it fell back. Today, it trades at around $4.50 per share.

Now, with the 25% tariff on steel, an opportunity among fixer-upper stocks may be at hand. Even if the tariff serves as more of a negotiating tactic, steel production in the U.S. will likely rise. AKS stands to benefit directly.

Analysts predict the company will earn 68 cents per share this year. This brings the company’s forward price-earnings (P/E) ratio to just above 6.6. Wall Street also expects consensus 2019 profits to come in at 80 cents per share, taking the P/E down further.

Investors should note some level of risk. Supporting a long-term debt of over $2.1 billion coupled with pension obligations of around $870 million pose a challenge for a company with a $1.44 billion market capitalization. If profits continue increasing, and the valuation rises to the steel industry’s current average P/E of 29, debt and pension burdens should lighten considerably.

Fixer-Upper Stocks: Chesapeake Energy Corporation (CHK)

Warren Buffett said, “You only find out who is swimming naked when the tide goes out.” Chesapeake Energy Corporation (NYSE:CHK) grotesquely exposed itself when energy prices fell in the middle of the decade.

The low prices left the Oklahoma City-based exploration and production (E&P) firm unable to manage its debt. The resignation and apparent suicide of founder Aubrey McClendon dealt a further blow to the natural gas company. CHK stock plunged into the single-digits and remained there as many questioned its ability to survive.

However, the company fought back and has stabilized itself. CHK has sold and continues to sell off assets, making it stand out among fixer-upper stocks. This has allowed it to pay off much of its debt. Moreover, higher energy prices have helped the company return to profitability. As debt levels recede and profits rise, CHK has positioned itself to clean up its balance sheet and drill for profits.

Moreover, Chesapeake remains the second-largest natural gas producer in the country. As more export terminals come online, CHK will be able to sell natural gas in previously unreachable markets in Europe and Asia.

CHK stock can not only recover but prosper from this recovery. The stock has recovered from levels that reached as low as $2.53 earlier this year. Even now that it trades above $4 per share, while its P/E ratio stands at just above 5. In comparison, CHK traded at a 24 P/E ratio at the end of 2014. With profits remaining steady, Chesapeake can again reach that multiple once debt levels fall and confidence returns.

Fixer-Upper Stocks: JCPenney Company Inc (JCP)

The decline of the mall and the advent of e-commerce have hit two traditional mall retailers hard. Both J C Penney Company Inc (NYSE:JCP) and Sears Holdings Corp (NASDAQ:SHLD) have seen their stocks fall below $3 per share as many call their future survival into question. High traffic in the malls during last year’s Christmas shopping season, however, signaled to investors that brick-and-mortar retail has not died, it is merely shrinking.

Still, this situation does not automatically turn these stores into fixer-upper stocks. Lower mall traffic will only leave room for one of these stores. Of the two, Plano, Texas-based JCPenney will likely be the one to survive.

For one, JCP fights aggressively to remain a viable business. Although I believe they often rely too much on cost-cutting, the low costs have brought traffic back to its stores. Moreover, Sears continues to sell off its most profitable brands such as Craftsman (and possibly Kenmore in the near future) merely to survive for a few more quarters. JCPenney has filled some of this void by bringing back appliance sales. As Sears continues down a long-term path to liquidation, JCP will probably find itself positioned to take more business from its competitor.

Analysts believe JCP will return to profitability in 2019. Moreover, the company trades at a book value of 0.61. Its real estate assets alone hold more value than its current market cap, which stands at about $835 million.

JCP stock currently trades at around $2.50 per share. The sudden departure of CEO Marvin Ellison stoked uncertainty. I expect the CEO search along with its $4.2 billion in long-term debt will keep JCP stock in the single digits for the foreseeable future. However, as SHLD fades and JCP finds or takes over profitable niches, I think JCP stock can recover.

Fixer-Upper Stocks: PDL BioPharma Inc (PDLI)

Among fixer-upper stocks, Incline Village, Nevada-based PDL BioPharma Inc (NASDAQ:PDLI) finds itself at a crossroads. Following the expiration of patents on its blockbuster drugs Avastin and Herceptin, its income dwindled. They suspended their dividend, and now PDLI has to look for a new source of income. They bought Noden Pharma in 2016. However, despite this purchase, net income has continued to fall.

PDLI stock saw a massive drop from the high of $10.10 per share it reached in the summer of 2014. Still, despite its challenges, PDLI has maintained a positive but falling net income. The company earned 71 cents per share in 2017. Analysts expect income to fall to 22 cents per share this year and rise to only 25 cents per share in 2019.

Where and how PDLI stock will come back remains unclear. However, with the stock trading at just under $2.70 per share, the P/E ratio stands at around 12. A more compelling ratio is its price-book value, which stands at under 0.5. In fact, its market cap stands at just over $400 million.

As of the end of Q1, the company held $405 million of cash on its balance sheet. This cash gives the company a good deal of flexibility. Merely bidding PDL up to its book value, reported at $843 million at the end of Q1, would more than double the value of PDLI stock. Once the company can find its next large source of revenue, PDLI stock should again exceed its book value and could even revive its dividend.

As of this writing, Will Healy is long CHK stock. You can follow Will on Twitter at @HealyWriting.