Herb Swanson/Bloomberg News

It’s time to question the financials of Green Mountain Coffee Roasters.

Shares in the company were halved in value on Thursday after the company reported disappointing second-quarter earnings Wednesday evening and forecast slower growth for its 2012 fiscal year.

The size of the drop in the stock suggests investors have concerns other than a slower growth rate.

A major one is whether Green Mountain has been using accounting maneuvers to make its profit look stronger than it is. David Einhorn, who manages the Greenlight Capital hedge fund, questioned the company’s financials in a presentation at a conference in October last year.

Green Mountain, based in Waterbury, Vt., sells single-cup coffee pods and brewers, and, until the fall of last year, had the best-performing stock on major exchanges over the prior five years.

The high-flying shares drew skeptics, who started to examine Green Mountain’s books for signs of weakness. One area that Mr. Einhorn highlighted was Green Mountain’s capital expenditures, the money the company spends on items like new factories and machines.

While capital expenditures are a cost for a company, they don’t show up all at once in the income statement. A company that wants to make itself look more profitable can take expenses that should be immediately counted in the income statement and classify them as capital expenditures. This was the main accounting trick used in the enormous fraud carried out by WorldCom, the telephone company that collapsed in 2002.

Is there any way to assess whether Green Mountain’s capital expenditures should be designated as expenses?

A starting place is a metric called free cash flow. This measures cash flows from the company’s core business of selling coffee and brewers and subtracts cash spent on capital expenditures. Typically, a healthy, somewhat mature company will produce positive free cash flow, because its core operations are producing more than enough money to cover capital expenditures.

Last year, as in prior years, Green Mountain had negative free cash flow. Capital expenditures of $283.4 million dwarfed cash flow from core operations of $785,000, resulting in negative free cash flow of $282.7 million.

It’s possible that Green Mountain needed to make big capital expenditures to buy new machines to keep up with strong demand for its products. But Mr. Einhorn was skeptical about that theory in his presentation.

On one slide, he estimated how much extra capital expenditure would be needed to produce extra coffee pods. Mr. Einhorn’s estimates were substantially less than the amounts of capital expenditure Green Mountain had forecast for new production capacity.

There’s another way to gauge some of Green Mountain’s capital expenditures that doesn’t rely on estimates from Mr. Einhorn, whose fund is likely betting against the company’s shares. That is to look at capital expenditures the company has forecast for new buildings. Those can then be compared with available cost figures in public documents for some of the buildings.

In November, Green Mountain said it was going to spend $175 million in 2012 on buildings, a total that does not include the machines that will operate in some of the buildings. (It cut that forecast to $165 million on Wednesday.)

In November, Green Mountain’s chief financial officer, Frances Rathke, said on a conference call, “The big pieces of the $175 million are Virginia and Essex, Vt.”

But a document filed last July with the Vermont Agency of Natural Resources said substantial additions to a Green Mountain facility in Essex, Vt. would cost $18 million. In a news release last October, Green Mountain said the Virginia building was going to cost $15 million, adding that the purchase was expected to close in December. The company has also said it’s expanding a facility in Waterbury, Vt. A document from 2010 said that was going to cost $14 million, but didn’t specify when that would be spent.

Those three public cost figures add up to just under $50 million, well short of Green Mountain’s $165 million new 2012 forecast for capital expenditures on buildings.

Of course, the buildings could cost more than the figures contained in the public documents. For instance, the news release about the Virginia facility said that Green Mountain planned to invest $180 million at that location in the first five years. However, it didn’t specify the type of capital expenditures that make up the $180 million.

Green Mountain says it can explain the difference between the $50 million of building costs derived from public documents and the company’s $165 million forecast. Suzanne DuLong, Green Mountain’s head of investor relations, said in an e-mail, “Property is only a piece of the estimated investment. The estimated $165 million is to buy and build out manufacturing facilities and enter into new office space.”

And asked whether Green Mountain was improperly capitalizing expenses to pad profits, Ms. DuLong said in the e-mail: “We adhere to recognized accounting regulations and principles including those around our capital expenditures.”