LONDON -- Right now, I'm trawling through the FTSE 100 and double-checking for blue chips that may be flattering their profits.

You see, many companies these days report "underlying" earnings, which are calculated by excluding costs the firm deems to be "exceptional." Trouble is, some companies are more cavalier than others when it comes to sweeping awkward expenses away from the headline figures.

Today, I'm looking at GlaxoSmithKline (LSE: GSK.L) (NYSE: GSK) to see if its reported earnings have been distorted significantly by exceptional, one-off, or unusual items. I've extracted the following statistics courtesy of S&P Capital IQ:

Year to Dec. 31

2007

2008

2009

2010

2011

Profit before unusual items (in millions of pounds)

7,588

8,161

8,462

8,599

7,738

Restructuring charges (in millions of pounds)

(338)

(1,123)

(835)

(1,348)

(592)

Gain on sales of assets and investments

98

232

481

187

867

Asset writedowns (in millions of pounds)

-

-

-

(130)

(158)

Legal settlements (in millions of pounds)

104

(611)

(513)

(4,001)

(157)

While annual figures can provide some insight into how a business has performed, I reckon looking back over several years provides a better view of possible problems in relation to one-off costs.

So between 2007 and 2011, my stats tell me GlaxoSmithKline reported cumulative profits before exceptional items and tax of 40.5 billion pounds. However, aggregate exceptional costs came to 7.9 billion pounds -- equivalent to a significant 20% of cumulative "underlying" profits.

Restructuring charges are often stripped out by companies as exceptional items, but you need to watch out for companies where restructuring seems to be a constant state of affairs. In GlaxoSmithKline's case, it's taken significant charges in each of the last five years, as the pharmaceutical industry continues to slim itself down in the absence of new blockbuster drugs.

Legal bills have also had a big impact on GlaxoSmithKline's bottom line in the last five years. They totaled more than 5 billion pounds. Although the major hit came in 2010, these charges also seem to be an ever-present cost of business.

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