The gold miners’ stocks have skyrocketed this year as investors started returning to this long-abandoned sector. Many have doubled since January, with plenty tripling or even quadrupling. Naturally such fast gains raise concerns about whether they are actually fundamentally justified or merely the product of fleeting sentiment that could reverse. Gold miners’ latest quarterly results offer great fundamental insights.

Companies trading on the US stock markets are required by the Securities and Exchange Commission to file quarterly earnings reports four times a year. For normal quarters that don’t end fiscal years, these 10-Q reports are due 45 calendar days after quarter-ends. They are a great boon to financial-market transparency and investors seeking to understand companies, yielding a treasure trove of information.

The gold miners are no exception, so about 6 weeks after quarter-ends I eagerly look forward to digging into their latest quarterly reports to see how they are faring I’d love to analyze these results sooner, but this industry has always inexplicably pushed the limits of that 45-day legal window for filing. That’s irritating in this era of computerized accounting systems that can instantly produce real-time data on demand.

Given the extraordinary market events of te first quarter of 2016, it’s an exceedingly important one to understand what’s going on with the gold miners fundamentally. Q1’16 saw the flagship NYSE Arca Gold BUGS Index better known by its symbol HUI blast up a staggering 60.3%!  While that was driven by gold powering 16.1% higher, the mining stocks’ 3.7x upside leverage to their metal was still quite high.

The most-popular gold-stock investment vehicle remains Van Eck’s GDX VanEck Vectors Gold Miners ETF. With a composition very similar to that venerable benchmark HUI, GDX enjoyed one heck of a Q1 as well with a huge 45.6% gain. This dominant gold-stock ETF doesn’t really have any meaningful competition, with assets running 38.2x those of the next-largest normal 1x long major-gold-miners ETF.

Thus the gold miners GDX’s managers include in their leading ETF are the definitive list of this sector’s biggest and best. While individual gold miners’ weightings in GDX are constantly tweaked, and smaller component companies are replaced from time to time, GDX inclusion is this industry’s gold standard. So that’s where I go every quarter to get my population of major gold miners to analyze their quarterly results.

As of the middle of this week, GDX had 39 holdings. These elite gold miners are overwhelmingly traded in the US stock markets, with 78.9% of this ETF’s weighting. That’s followed by Australia at 11.0% and Canada at 6.9%.  I was glad to see the weighting of Chinese companies trading in Hong Kong fall under 2.0%. Chinese financial-reporting standards are atrocious, with muddled opaqueness defying belief.

Before I founded Zeal over 16 years ago, I was a certified public accountant working at a Big Six firm auditing publicly-traded mining companies. Ever since, I’ve been deeply immersed in researching this contrarian sector for investment and speculation. And even with this exceptional background, I find the Chinese quarterly reports utterly confounding. It’s not a language thing, they intentionally obscure key data.

But thankfully the American, Canadian, and Australian gold miners that dominate this industry tend to do an excellent job with their quarterly reports. They transparently provide an abundance of key data going far beyond legal SEC reporting requirements. That helps investors understand what is actually going on with their companies fundamentally, critical knowledge that is essential for success in this realm.

Every quarter I dig through these reports and fill a spreadsheet with a wide array of data from the results. This helps me decide which elite gold miners I want to invest in, and equally importantly which I’d rather avoid for a variety of reasons. These tables summarize some key data from GDX’s top 34 holdings, or 96.7% of this leading gold-stock ETF’s weightings. That’s how many happen to fit in our standard chart size.

Each company’s symbol and exchange listing purchased by GDX’s managers is followed by its weight in that ETF, and its market capitalization as of the middle of this week. GDX largely weights components by market cap, which is certainly the most logical way to do it.  Market cap is actually an important thing to consider for investing, as the larger a company is the more capital inflows it will need to propel it higher.

That’s followed by price-to-earnings ratios, the foundation of fundamental analysis. Throughout all the stock markets, all stocks eventually migrate to some reasonable multiple of their underlying companies’ corporate profits. As I’ll discuss below, the gold miners’ P/E ratios look absolutely abysmal today. These companies are either showing GAAP losses or profits so trivial that they lead to ridiculously-high P/Es.

Naturally gold-mining profitability is purely a function of prevailing gold prices relative to the costs of actually producing this metal. The next few columns show the GDX miners’ cash costs per ounce and all-in sustaining costs per ounce in Q1’16, as well as their AISC outlooks for full-year 2016.  The greater the delta between mining costs and gold prices, the more profitable these elite gold miners will become.