What do these three companies have in common? Yes, they’re all different! And I reckon that’s the key to a good ISA selection: a well diversified portfolio of leaders in their field.

It’s pretty hard to argue against ARM Holdings (LSE: ARM), the world-beating mobile computing chip specialist. The value of ARM shares has multiplied sevenfold in the past decade, to 1,004p as I write. The price has been flat over the past three years, but earnings have been growing nicely and the P/E rating of the shares has fallen to a more attractive level.

Forecasts for this year suggest a 43% rise in earnings per share (EPS), giving us  a P/E multiple of 29. At around twice the FTSE 100 average, that might seem high, but it’s the lowest it’s been in years and is good value for such a strong growth candidate. The other attraction with ARM is dividend that’s growing well ahead of inflation — by 25% in 2015, with a further 12% hike forecast for this year. Share price rises have kept the yield down, but at this rate you’d soon earn a decent yield on your purchase price if you bought today.

Back when I first started looking at ARM, I liked to point out that mobile computing was still in its infancy. Today, years later, it still is! City analysts have a strong buy consensus out for ARM, and they have my full agreement.

Buy on weakness

BAE Systems (LSE: BA) is very much a leader in its field, although tightened belts in aerospace and defence have squeezed earnings growth. According to forecasts, there should be no real change in earnings between 2013 and 2017. The share price has lost 5% over the past 12 months, to 504p, but over five years we’re still looking at a 51% rise that’s way ahead of the 3% the FTSE 100 has managed.

On top of that, BAE is paying dividends that easily beat the average, with shareholders having enjoyed a 4.2% yield in 2015 and with 4.3% on the cards for this year. The company has a policy of maintaining “long-term sustainable cover of around two times underlying earnings,” and we should hear more when interim results are released on 28 July.

Again, the brokers are pretty bullish about BAE, and so am I — for the long term, certainly, and that’s what counts for an ISA.

Top telly provider

I’ve suggested before that BT Group is my pick of the telecoms sector, but I’m impressed by the prospects for Sky (LSE: SKY) too, and when we think about the supply of TV content it’s still head and shoulders above its rivals. We’ve seen EPS flatten-off over the past couple of years, but there’s an 11% lift forecast for the year to June 2016. At the interim stage we heard of a 12% rise in underlying operating profit and a 10% rise in underlying EPS, so that forecast is probably not far off the mark.

On a forward P/E of around 16.5, Sky shares might not seem screamingly cheap. But with strong growth potential in the coming years and with a progressive dividend policy, I see good value for ISA investors here.

No time to lose

Anyway, whether you like these three or prefer others, make haste — for the current ISA allowance ends in just a week.

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