BT’s (LSE: BT.A) share price is changing hands close to its 23 May 12-month high of £1.79.

This may put off some investors from considering buying the stock, thinking it cannot rise much further. Others may see it as a good time to buy as bullish momentum appears to be in play.

Having spent years as a senior investment bank trader and private investor I know neither approach is helpful in investing.

When looking at a stock for potential share price gains, I am only interested in two things. First, its earnings growth forecasts, as this is what a firm’s share price is driven by over the medium and long term. And second, how much value remains in it as this affects how far that growth will…