Warren Buffett attracts a lot of attention. As the world's third-richest person and most celebrated investor, thousands try to glean what they can from his thinking processes and track his investments.

While we can't know for sure whether Buffett is about to buy Sirius XM (Nasdaq: SIRI) -- he hasn't specifically mentioned anything about it to me -- we can discover whether it's the sort of stock that might interest him. Answering that question could also inform whether it's a stock that should interest us.

In his most recent 10-K, Buffett lays out the qualities he looks for in an investment. In addition to adequate size, proven management, and a reasonable valuation, he demands:

  1. Consistent earnings power.
  2. Good returns on equity with limited or no debt.
  3. Management in place.
  4. Simple, non-techno-mumbo-jumbo businesses.

Does Sirius XM meet Buffett's standards?

1. Earnings power
Buffett is famous for betting on a sure thing. For that reason, he likes to see companies with demonstrated earnings stability.

Let's examine Sirius XM's earnings and free cash flow history:

Siri

Source: Capital IQ, a division of Standard & Poor's. Free cash flow is adjusted based on author's calculations.

Over the past five years, Sirius XM had a difficult time producing earnings and free cash flow. However, that's changed since fiscal 2010, and the company is now profitable.

2. Return on equity and debt
Return on equity is a great metric for measuring both management's effectiveness and the strength of a company's competitive advantage or disadvantage -- a classic Buffett consideration. When considering return on equity, it's important to make sure a company doesn't have an enormous debt burden, because that will skew your calculations and make the company look much more efficient than it actually is.

Since competitive strength is a comparison between peers, and various industries have different levels of profitability and require different levels of debt, it helps to use an industry context.

Company

Debt-to-Equity

Return on Equity (LTM)

Return on Equity (5-Year Average)

Sirius XM Radio

612%

70%

N/A

Apple (Nasdaq: AAPL)

0%

42%

30%

Motorola Solutions (NYSE: MSI)

32%

7%

0%

Pandora (NYSE: P)

68%

0%

(42%)

Source: Capital IQ, a division of Standard & Poor's. N/A = not applicable due to negative equity one or more years.

Having recently turned profitable, Sirius XM generated an enormous return on equity, though that is due in large part to the company's substantial debt.

3. Management
CEO Mel Karmazin has been at the job since 2004 (when it was just Sirius Satellite Radio). Prior to that, he'd spent several years at other broadcasters, including CBS and Viacom .

4. Business
Fans of Sirius will point to the lack of meaningful direct competition in the satellite radio industry, but the medium is new and could be vulnerable to technological disruption from indirect competitors.

The Foolish conclusion
Regardless of whether Buffett would ever buy Sirius XM, we've learned that while the company has tenured management, it doesn't particularly exhibit some of the other characteristics of a quintessential Buffett investment: consistent earnings, high returns on equity with limited debt, and a straightforward industry.

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