The economic effects of the COVID-19 virus have sent stocks spiraling, but oil and gas companies have fallen harder than most. The price war between Saudi Arabia and Russia has inflicted extra pain, putting most U.S. producers at much higher probability of defaulting on their debt.

Eleven of the biggest independent oil producers reviewed have seen their chances of default spike in recent weeks, according to the S&P Global Market Intelligence perception of default signal model that calculates the likelihood of a company defaulting on its debt or entering bankruptcy protection over a one- to five-year horizon.

Ovintiv Inc. is in the most perilous position, with the model indicating the company has a better than 31% chance of default or bankruptcy. On Feb. 20, the odds of that occurrence were at less than 5%.

Noble Energy Inc.'s chances of default or bankruptcy have also increased considerably and now stand at approximately 26%. On Feb. 23, they stood at a little more than 3%.

Occidental Petroleum Corp.'s chances of a potential default or bankruptcy stood at 12.9% March 19, relatively low compared to peers but still twice what it was just 10 days earlier. The chances of Apache Corp.'s defaulting or seeking bankruptcy have increased nearly 10 percentage points in a matter of days to over 18%.

A look at the stock prices of the 11 producers shows nearly all have been decimated since the start of 2020. None of them have sustained share value losses of less than 50%.

Most independents have seen their share prices sliding for the past 12 months, but that decline picked up steam as oil prices started to decline in early 2020. The bottom truly fell out, though, after Saudi Arabia announced it would increase production in an already saturated market on the weekend of March 7-8. When the markets opened in the U.S. on March 9, stocks of independent oil producers fell dramatically and have continued to drop since.

"Certainly from a sentiment perspective, around equities, it feels really bad," KeyBanc analyst Leo Mariani said. "In 2016, there was this hope that things look bad right now, but things will recover in a year or so. Now, people are saying, 'Look out below.'"

Three of the 11 producers have seen their share prices drop more than 80% since Jan. 2. Ovintiv has seen the largest drop in its stock price in terms of percentage, falling more than 88%. The company's stock, which stood at $23.70 per share on Jan. 2, had already slipped to $7.94 per share when the New York Stock Exchange closed March 6. When the market closed March 9, it had fallen to $2.22 per share. It had rebounded slightly to $2.81 per share at the end of trading March 17.

Shares of Noble dropped nearly 83% between Jan. 2 and March 17. The company's stock stood at $24.13 per share Jan. 2 but had fallen to $13.32 per share by March 6. It shed nearly $4 on March 9, and closed March 17 at $4.19 per share.

Apache stock did little better, losing 82.4% of its value year to date through March 17. Apache actually started the year on a high note, seeing shares rise as high as $33.54 at the market's close Jan. 15 on news of positive drilling results from its play off the coast of Suriname. But the company's shares fell nearly $15 in one day on March 9, closing at $9.55. Its downward spiral has continued since.

The two hardest-hit companies in terms of price loss are two Permian powers, Diamondback Energy Inc. and Pioneer Natural Resources Co. Diamondback's stock stood at $92.65 per share Jan. 2 and had lost more than $40 by March 6. When the market closed March 9, shares were down another $22; they stood at $20.23 at the close of the Nasdaq on March 17, a loss of 78.2% since the start of the year.

Pioneer entered 2020 with shares trading above $152 but had fallen to $105.12 by March 6. The company's stock lost a staggering $38.81 in one day on March 9 and closed March 17 at $57.53 per share, a decline of 62.2% year-to-date.

Occidental, whose stock was trading above $65 per share 52 weeks ago, has seen its stock price decline consistently since it started its $57 billion pursuit of Anadarko Petroleum Corp. The slide has picked up speed since the start of the year, as the company's stock price fell from $42.58 per share on Jan. 2 to $11.33 per share on March 17, a decrease in value of 73.4%. On March 18, shares slid to as low as $9.05, the stock's lowest level since at least 1980.

Concho Resources Inc., another Permian-only producer, has seen its shares drop more than 56% since the start of the year. Standing at $86.95 per share on Jan. 2, its stock had tumbled to $58 per share by March 6. It has since fallen more than $20, closing March 17 at $37.99 per share.

With independents selling at a significant discount, some investors could sense an opportunity. Industry observers, however, believe it could be several years before buying the top names in the sector pays off.

"What every oil and gas producer is currently focused on, as the first line of defense, is cutting capital spending: in many cases, quite sharply, by 30% or even more. Some reductions in corporate costs are also likely, but the main driver will be to slow drilling activity and postponed projects," Raymond James analyst Pavel Molchanov said.

"By responding rapidly in this way, the large, investment-grade companies will be able to steer themselves through this exceptionally tough time in the industry. In fact, they may even benefit, over a long-term timeframe, by taking advantage of this crisis as an opportunity to pick up cheap, distressed assets when some of the smaller players with excessive leverage end up going through bankruptcy," Molchanov said.

Morningstar analyst David Meats said "E&Ps are cheap" at the moment, but shareholders will need to be patient.

"We expect a very rough couple of years. The market is pricing in current prices, or at most $40-45 [per barrel], in perpetuity. That doesn't make sense; the marginal cost is still above $50 [per barrel]," Meats said. "However, they have to survive the next couple of years to see the benefit, so their balance sheet is key."