Many investors, especially during earnings season, seem to focus on the income statement. How much revenue was there? How much net income was there? Yet that focus can be dangerous, because the balance sheet actually tells us a lot about how the company is doing, and what it's likely to be doing in the not-too-distant future. Today, I'll focus on two balance sheet line items, accounts receivable and inventories, and how they relate to sales.

In Thornton O'Glove's book Quality of Earnings, he calls the analysis of A/R and inventory growth relative to sales the "best method" to get ahead of Wall Street analysts:

One of these simple ploys -- the best method I have ever discovered to predict future downwards earnings revisions by Wall Street security analysts -- is a careful analysis of accounts receivables and inventories. Learn how to interpret these ... a larger than average accounts receivable situation, and/or a bloated inventory. When I see these, bells go off in my head.

If A/R goes up significantly faster than sales, then the company could be stuffing the channel, pulling sales in from the future. It can only do so for so long before customers get fed up and stop buying for a while. Then the company ends up missing revenue and earnings, and the stock price gets whacked.

Similarly, if inventory is rising significantly faster than sales, that could mean demand is slowing down, and a big inventory writedown might be coming. Alternately, sales will be hurt when the company uses large markdowns just to clear out inventory.

Note that I'm not talking about normal business-cycle stuff. Many retailers build up inventory prior to the holiday season in order to meet expected demand. That's normal. Instead, I'm looking for a big disconnect between the growth of sales and the growth of A/R or inventory. That's a potential sign of a risky investment, and it makes me dig a bit deeper to see what's going on.

Let's apply this to Joy Global (Nasdaq: JOYG), the mining equipment manufacturer. Here's what the company has reported for the past four-quarter period and for the past two year-over-year periods. I've also included a couple of others for comparison's sake.

Metric

Joy Global

Bucyrus International (Nasdaq: BUCY)

Oshkosh (NYSE: OSK)

Revenue growth, TTM

(6.2%)

3.7%

65.1%

A/R growth, TTM

(0.9%)

15.1%

65.9%

Inventory growth, TTM

(12.8%)

60.4%

(0.2%)

       

Revenue growth, year ago

17.4%

23.4%

(18.9%)

A/R growth, year ago

1.6%

33.9%

(55.1%)

Inventory growth, year ago

(0.2%)

19.2%

(27%)

       

Revenue growth, 2 years ago

24.9%

128.7%

26.9%

A/R growth, 2 years ago

29.1%

1.5%

12.1%

Inventory growth, 2 years ago

19.4%

17.1%

22.2%

Source: Capital IQ, a division of Standard & Poor's; TTM = trailing 12 months.

All three companies have done a good job of matching A/R and inventory growth with revenue growth over the past few years. All except Bucyrus, that is. In the past year, it let A/R and, especially, inventory grow a lot faster than revenue did. Given its history, I'd expect it to get that back under control, but investors should keep an eye open to make sure that happens. I don't see any problems in the handling of this part of working capital for either Joy Global or Oshkosh over the past few years. And that's nice to see.

Pay attention to the balance sheet, plug a few numbers into a simple spreadsheet, and, according to O'Glove, you can get ahead of Wall Street. This easy analysis, along with a bit of thought, gives you the potential to save yourself the heartache of seeing your investment get sharply cut when a company reports a "surprisingly" disappointing quarter.

The warning signs are often there ahead of time. This tool helps you see them.

True to its name, The Motley Fool is made up of a motley assortment of writers and analysts, each with a unique perspective; sometimes we agree, sometimes we disagree, but we all believe in the power of learning from each other through our Foolish community. Try any of our Foolish newsletter services free for 30 days.

Fool analyst Jim Mueller doesn't have a position in any company mentioned. He works with the Fool's Stock Advisor newsletter service. The Motley Fool is investors writing for investors.