ARM Holdings (LSE: ARM) looks cheaper than it has done for years, in my opinion. The chip designer’s share price has fallen by 27% from its 52-week high of 1,332p last year.

ARM shares now trade on a 2016 forecast P/E of 28, falling to a P/E of 25 for 2017. Although I wouldn’t normally buy shares with such a demanding valuation, I’m considering whether ARM should be an exception.

The firm’s profits have risen by an average of 31% per year since 2010, and this pace looks set to continue. Analysts are pencilling-in earnings per share growth of 45% for 2016, and 15% next year.

However, I believe these figures could understate ARM’s long-term potential. The company’s recent acquisition of imaging and computer firm Apical is an example of how ARM’s designers are looking at a future beyond smartphones. They’re targeting new markets such as connected vehicles and robotics.

If ARM can deliver winning products for just a handful of new markets, the firm’s growth could continue for many years. At less than 1,000p, I think ARM could prove to be a profitable long-term buy.

This could be a value opportunity

Investors are much less optimistic about the outlook for aerospace and automotive engineer GKN (LSE: GKN). The firm’s shares have fallen by 26% over the last year and currently trade on a 2016 forecast P/E of just 9.6.

The shares even look good value on a more demanding measure, price-to-free-cash-flow. GKN currently trades on a trailing P/FCF ratio of just 13. This highlights the firm’s ability to generate surplus cash for shareholder returns.

Although GKN’s dividend yield of 3.3% is below the FTSE 100 average of 4%, I reckon this business could deliver decent medium-term growth.

The firm’s acquisition of Fokker last year contributed an extra £159m to GKN’s aerospace sales during the first quarter. In the same period, GKN gained market share in the automotive sector. Organic sales grew by 4%, against a global increase in production rates of only 1%.

In my view, GKN shares are currently priced to deliver limited growth. If things turn out better than expected, then the shares could deliver decent gains from here.

Don’t write this company off

It’s a similar story at interdealer broker Tullett Prebon (LSE: TLPR). Tullett’s shares trade on just 10 times forecast earnings, with earnings per share expected to rise by just 3% this year.

The firm is seen as a bit of a dinosaur, as its core voice brokerage business — where traders negotiate bespoke trades with customers over the phone — is in decline. But Tullett boss John Phizackerley is working hard to modernise and expand this business.

Since taking charge, Mr Phizackerley has overseen the purchase of oil broker PVM and of rival ICAP’s brokerage business. Tullett is also investing in increasing its electronic trading facilities to meet future requirements.

Tullett shares currently offer a 2016 forecast yield of 5.2%, which should be covered nearly twice by earnings. The firm also had net cash of £157m at the end of last year, providing a further margin of safety for income investors.

I rate Tullett as a strong medium-term buy, and have recently added the shares to my own watch list.

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