E10 is a concept invented by Prof. Robert Shiller, who uses E10 for his Shiller P/E calculation. E10 is the average of the inflation adjusted earnings of a company over the past 10 years.
Idemitsu Kosan Co's adjusted earnings per share data for the three months ended in Mar. 2026 was 円97.450. Add all the adjusted EPS for the past 10 years together and divide 10 will get our e10, which is 円119.72 for the trailing ten years ended in Mar. 2026.
During the past 12 months, Idemitsu Kosan Co's average E10 Growth Rate was 20.80% per year.
During the past 3 years, the average E10 Growth Rate was 28.50% per year.
During the past 5 years, the average E10 Growth Rate was 29.10% per year.
Please click Growth Rate Calculation Example (GuruFocus) to see how GuruFocus calculates Wal-Mart Stores Inc (WMT)'s revenue growth rate. You can apply the same method to get the E10 growth rate using E10 data.
During the past 13 years, the highest 3-Year average E10 Growth Rate of Idemitsu Kosan Co was 30.60% per year. The lowest was -1.50% per year. And the median was 19.80% per year.
During the past 13 years, the highestShiller PE Ratio of Idemitsu Kosan Co was 34.13. The lowest was 8.65. And the median was 13.83.
Idemitsu Kosan Co (TSE:5019) E10 Explanation
If a company grows much fast than inflation, E10 may underestimate the company's earnings power. Shiller PE Ratio can seem to be too high even the actual P/E is low.
For the Shiller P/E, the earnings of the past 10 years are inflation-adjusted and averaged. The result is used for P/E calculation. Since it looks at the average over the last 10 years, the Shiller P/E is also called PE10.
The Shiller P/E was first used by professor Robert Shiller to measure the valuation of the overall market. The same calculation is applied here to individual companies.
Idemitsu Kosan Co's Shiller P/E Ratio of today is calculated as
* For Operating Data section: All numbers are indicated by the unit behind each term and all currency related amount are in USD. * For other sections: All numbers are in millions except for per share data, ratio, and percentage. All currency related amount are indicated in the company's associated stock exchange currency.
During the past 13 years, the highest Shiller P/E Ratio of Idemitsu Kosan Co was 34.13. The lowest was 8.65. And the median was 13.83.
Be Aware
Shiller PE Ratio works better for cyclical companies. It gives you a better idea on the company's real earnings power.
Idemitsu Kosan Co E10 Related Terms
Idemitsu Kosan Co E10 Historical Data
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The historical data trend for Idemitsu Kosan Co's E10 can be seen below:
* For Operating Data section: All numbers are indicated by the unit behind each term and all currency related amount are in USD. * For other sections: All numbers are in millions except for per share data, ratio, and percentage. All currency related amount are indicated in the company's associated stock exchange currency.
For the Oil & Gas Refining & Marketing subindustry, Idemitsu Kosan Co's Shiller PE Ratio, along with its competitors' market caps and Shiller PE Ratio data, can be viewed below:
* Competitive companies are chosen from companies within the same industry, with headquarter located in same country, with closest market capitalization; x-axis shows the market cap, and y-axis shows the term value; the bigger the dot, the larger the market cap. Note that "N/A" values will not show up in the chart.
Idemitsu Kosan Co Shiller PE Ratio vs Oil & Gas Industry
For the Oil & Gas industry and Energy sector, Idemitsu Kosan Co's Shiller PE Ratio distribution charts can be found below:
* The bar in red indicates where Idemitsu Kosan Co's Shiller PE Ratio falls into.
E10 is a concept invented by Prof. Robert Shiller, who uses E10 for his Shiller P/E calculation. When we calculate the today's Shiller P/E ratio of a stock, we use today's price divided by E10.
What is E10? How do we calculate E10?
E10 is the average of the inflation adjusted earnings of a company over the past 10 years. Let's use an example to explain.
If we want to calculate the E10 of Wal-Mart (WMT) for Dec. 31, 2010, we need to have the inflation data and the earnings from 2001 through 2010.
We adjusted the earnings of 2001 earnings data with the total inflation from 2001 through 2010 to the equivalent earnings in 2010. If the total inflation from 2001 to 2010 is 40%, and Wal-Mart earned $1 a share in 2001, then the 2001's equivalent earnings in 2010 is $1.4 a share. If Wal-Mart earns $1 again in 2002, and the total inflation from 2002 through 2010 is 35%, then the equivalent 2002 earnings in 2010 is $1.35. So on and so forth, you get the equivalent earnings of past 10 years. Then you add them together and divided the sum by 10 to get E10.
Please note that we use the CPI data of the country/region where the company is headquartered. If the CPI data for that country/region is not available, then we will use the CPI data of the United States as default.
For example, Idemitsu Kosan Co's adjusted earnings per share data for the three months ended in Mar. 2026 was:
Idemitsu Kosan Co (TSE:5019) has a E10 of 円119.72 as of Mar. 2026. E10 represents the company's inflation-adjusted earnings per share over a 10-year period. View historical data on Idemitsu Kosan Co and its competitors.
Is Idemitsu Kosan Co's E10 too high?
Idemitsu Kosan Co's current E10 is 円119.72. Overall, Idemitsu Kosan Co has a GF Score™ of 65/100 and is considered Modestly Overvalued, reflecting its overall financial health beyond just this single metric.
How does Idemitsu Kosan Co's E10 compare to VLO and MPC?
Idemitsu Kosan Co's E10 of 円119.72 can be compared against companies in the Oil & Gas industry. See the competitive comparison table and distribution chart on this page for a detailed peer-by-peer breakdown.
What is a good E10 for an Oil & Gas company?
A good E10 depends on the Oil & Gas industry context. However, E10 should not be evaluated in isolation — investors should consider it alongside profitability, growth, and financial strength metrics. Use the industry distribution chart on this page to see where any company falls relative to its peers.
What does a high E10 mean?
A high E10 can signal that a stock is expensive relative to its fundamentals. E10 represents the company's inflation-adjusted earnings per share over a 10-year period. View historical data on Idemitsu Kosan Co and its competitors. Idemitsu Kosan Co's current E10 is 円119.72. However, context matters — high-growth companies often justify higher valuations. Always evaluate alongside other metrics like GF Score™ and GF Value™.
Is Idemitsu Kosan Co stock overvalued right now?
Based on GuruFocus' analysis, Idemitsu Kosan Co (TSE:5019) is currently considered Modestly Overvalued. The stock's GF Value™ is 円1,071.95, compared to a current price of 円1,223.50 — trading 14.1% above its estimated fair value. The current E10 is 円119.72. Idemitsu Kosan Co's overall GF Score™ is 65/100 with 4 warning signs to review. Investors should evaluate multiple metrics — including profitability, growth, and financial strength — before making a decision.
How is E10 calculated?
E10 is calculated from a company's financial statements. For Idemitsu Kosan Co (TSE:5019), the current E10 is 円119.72 as of Mar. 2026. GuruFocus calculates this using data sourced from SEC filings and annual reports. See the calculation section and 30-year financial data on this page for the full breakdown.
Is Idemitsu Kosan Co (TSE:5019) Overvalued in 2026?
Based on GuruFocus' analysis, Idemitsu Kosan Co stock appears to be overvalued.
The current stock price of 円1,223.50 is trading 14.1% above its estimated GF Value™ of 円1,071.95.
GuruFocus considers Idemitsu Kosan Co to be Modestly Overvalued.
Key valuation signals for TSE:5019:
E10: 円119.72
GF Value™: 円1,071.95 vs. price of 円1,223.50 (14.1% above fair value)
No single metric tells the full story. See the TSE:5019 stock analysis page for a complete view including 30-year financials, guru trades, and insider activity.
Idemitsu Kosan Co Ltd engages in a variety of activities globally that include petroleum products, oil exploration and production, coal, and other businesses. The company operates through five segments. The Basic Chemicals segment makes and sells olefins and aroma products. Electricity/Renewable Energy covers thermal, solar, and wind power generation, electricity sales, and solar business. Fuel Oil handles production, trading, and import/export of refined petroleum. The Highly Functional Materials segment includes lubricants, chemicals, electronic materials, paving materials, and agri-bio. The Resource segment explores, develops, and sells crude oil, natural gas, and coal. Others cover insurance and intra-group services. It generates the majority of its revenue from the Fuel oil segment.
65GF Score
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