Today I’ll be taking a closer look at diversified mining company BHP Billiton (LSE: BLT), and online takeaway delivery service Just Eat (LSE: JE). Should you be risking your money on either of these London-listed companies right now?

Huge appetite for growth

Food-to-go service Just Eat recently briefed the market with a trading update for the three months to 31 March. The company describes itself as the world’s leading digital marketplace for takeaway food delivery, and who can argue with that? It fulfilled 31.5m orders in the first quarter alone, 57% higher than Q1 2015, and up 41% on a like-for-like basis.

Just Eat connects takeaways and restaurants with customers and generates revenues by charging the food outlets a commission for each order placed via its website or app. The majority of Just Eat’s revenues are generated in the UK, but the company has expanded to Spain, Italy, Switzerland, Brazil, Mexico, Australia and New Zealand in recent years through acquisitions. The growth potential is obvious, busy lifestyles mean less cooking, more takeaways, and bigger profits.

Naturally you would expect Just Eat to be trading on sky-high earnings multiples, but forward price-to-earnings ratios of 39 and 27 for this year and next aren’t too demanding when considering the consensus forecasts of 58% and 48% for 2016 and 2017, respectively.

Poor value

Diversified mining company BHP Billiton has seen its shares fall by around 45% over the last 12 months, and you could understand investors viewing this as a potential buying opportunity. Indeed Swiss investment bank UBS recently confirmed its buy stance with a target price of £10.50. Far be it from me to argue with their infinite wisdom, but my personal view is rather more bearish.

Our friends in the City estimate underlying profits of £214m for the year to the end of June, representing a massive 88% collapse in earnings compared to last year. However, analysts are expecting an impressive 164% rebound next year, with profits leaping to £566m for fiscal 2017.

Based on these projections the current share price would leave BHP trading on 83 times forecast earnings for this year, falling to 31 for the year ending June 2017.Bearing in mind that over the last five year-ends the price-to-earnings ratio for BHP has ranged from 8 through to 15, the shares look very poor value indeed.

The verdict

Just Eat is a classic growth stock with huge growth potential given the worldwide appetite for takeaway food. The shares are trading well below December 2015 highs of 495p, and growth investors should view this as an opportunity to tap into the rapidly growing fast food market.

Despite the hefty share price falls this year, BHP Billiton is still far too expensive and too risky for me. If commodity prices don’t recovery soon, further falls could be on the cards and investing now could be like catching a falling knife.

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Bilaal Mohamed has no position in any shares mentioned. The Motley Fool UK has no position in any of the shares mentioned. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.