LONDON -- It's always worth keeping an eye on the earnings forecasts for your favorite companies, especially if you use forward P/E ratios to gauge when to buy and sell your shares.

You never know, if City brokers have been revising their projections of late, your investments may not be as cheap -- or expensive -- as you think!

Today I'm looking at the earnings per share forecasts for BT Group (LSE: BT-A.L) (NYSE: BT), the FTSE 100 fixed-line telecom operator. All my figures are courtesy of S&P Capital IQ.

The consensus for 2013 is for earnings per share of 25 pence, which puts the 226 pence shares on a modest forward P/E of 9.

However, the estimates suggest earnings may remain flat for the next four years before dropping slightly to 23 pence for 2017, at least according to City analysts.

The data from S&P Capital IQ also indicates BT Group's revenue may stall around the 18 billion pound mark and EBITDA stagnate at about 6 billion pounds during the next few years.

All told, the forecasts aren't great, with earnings essentially predicted to go nowhere between 2013 and 2017. But then again, that P/E of 9 looks like the market is already expecting earnings won't advance anytime soon.

Whether these projections make BT Group a buy, a hold, or a sell is of course up to you. To put the company's multiple into perspective, the FTSE 100 at 5,800 trades on a P/E of 11.4.

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