Companies with low debt, such as National Oilwell Varco, will be able to scoop up rivals and grab market share.

Here are the 10 S&P 500 energy and materials companies with the lowest debt-to-equity ratios as of Sept. 30, according to FactSet:


1. Helmerich & Payne Inc.
Ticker -- HP, -3.17%
Industry -- Contract Drilling
Long-term debt/ equity - Sept. 30 -- 10.9%
Average return on equity - five years through September 2015 -- 14.7%
Total return - 5 years through Jan. 8 -- 8%

2. National Oilwell Varco Inc.
Ticker -- NOV, -1.84%
Industry -- Oilfield Services/ Equipment
Long-term debt/ equity - Sept. 30 -- 15.3%
Average return on equity - five years through September 2015 -- 11.4%
Total return - 5 years through Jan. 8 -- -44%

3. Exxon Mobil Corp.
Ticker -- XOM, -1.95%
Industry -- Integrated Oil
Long-term debt/ equity - Sept. 30 -- 16.7%
Average return on equity - five years through September 2015 -- 22.3%
Total return - 5 years through Jan. 8 -- 13%

4. Chevron Inc.
Ticker -- CVX, -2.11%
Industry -- Integrated Oil
Long-term debt/ equity - Sept. 30 -- 17.9%
Average return on equity - five years through September 2015 -- 17.0%
Total return - 5 years through Jan. 8 -- 7%

5. Occidental Petroleum Corp.
Ticker -- OXY, -1.89%
Industry -- Oil and Gas Production
Long-term debt/ equity - Sept. 30 -- 19.6%
Average return on equity - five years through September 2015 -- 10.2%
Total return - 5 years through Jan. 8 -- -21%

6. Baker Hughes Inc.
Ticker -- BHI, -3.11%
Industry -- Oilfield Services/ Equipment
Long-term debt/ equity - Sept. 30 -- 22.2%
Average return on equity - five years through September 2015 -- -22%
Total return - 5 years through Jan. 8 -- 7.5%

7.Hess Corp.
Ticker -- HES, -3.10%
Industry -- Oil and Gas Production
Long-term debt/ equity - Sept. 30 -- 27.0%
Average return on equity - five years through September 2015 -- 9.7%
Total return - 5 years through Jan. 8 -- -42%

8. Marathon Oil Corp.
Ticker -- MRO, -10.25%
Industry -- Oil and Gas Production
Long-term debt/ equity - Sept. 30 -- 30.4%
Average return on equity - five years through September 2015 -- 7.3%
Total return - 5 years through Jan. 8 -- -50%

9. Valero Energy Corp.
Ticker -- VLO, -1.35%
Industry -- Oil Refining/ Marketing
Long-term debt/ equity - Sept. 30 -- 30.9%
Average return on equity - five years through September 2015 -- 14.2%
Total return - 5 years through Jan. 8 -- 248%

10. Pioneer Natural Resources Co.
Ticker -- PXD, -2.43%
Industry -- Oil and Gas Production
Long-term debt/ equity - Sept. 30 -- 31.1%
Average return on equity - five years through September 2015 -- 3.9%
Total return - 5 years through Jan. 8 -- 32%