Shares in pub company Greene King (LSE: GNK) were given a boost today with the release of an upbeat trading update. The company reported a rise in like-for-like (LFL) retail sales in the 40 weeks to 7 February of 2.2%, with the Spirit Managed business recording a rise of 1.1% in LFL sales during the same period.

Encouragingly, the Spirit integration is progressing well and Greene King has witnessed positive performance in rebranded trial sites. Synergies from the deal are also being delivered, which is helping Greene King to progress towards meeting its full-year guidance. In the current year that equates to growth in earnings of 9%, while looking ahead to next year, Greene King is expected to post a rise in its bottom line of 11%.

This strong rate of growth puts the company’s shares on a price-to-earnings growth (PEG) ratio of just one, which indicates that there’s at least 25% upside in the company’s share price. Although the outlook for the global economy is uncertain, Greene King appears to be a strong buy for the long term given its improving financial performance.

Uncertainty ahead

Also offering 25% upside is Prudential (LSE: PRU). It’s undergoing a difficult period at the moment for two main reasons. Firstly, its management team is changing and this brings a degree of uncertainty regarding its future progress. For example, Prudential has a new CEO and it will also have a new Chief Executive of its lucrative asset management arm, M&G.

Secondly, Prudential is suffering from weakening investor sentiment towards Asia-focused stocks. With Chinese growth slowing, there’s a concern that the world’s second largest economy will disappoint on the long-term growth front and this could hurt Prudential’s long-term expansion plans.

While this view is understandable given China’s soft landing, the reality is that a large number of Chinese will require financial products in future and Prudential is highly diversified and well-placed to benefit from this in the long run. With its shares trading on a PEG ratio of just 1.3, 25% upside is very much on the cards.

Turnaround trail

Meanwhile, AstraZeneca (LSE: AZN) also appears to be attractively priced at the present time. It trades on a price-to-earnings (P/E) ratio of just 15 which, given its future prospects, appears to be highly appealing.

Although AstraZeneca has struggled to come to terms with its patent losses and is expected to record a fall in its bottom line of 10% this year, it’s gradually turning its performance around. An acquisition programme has greatly strengthened its drug pipeline and with AstraZeneca’s balance sheet being strong and its cash flow being highly resilient, there’s scope for further, major acquisitions.

With a number of pharmaceutical companies trading on significantly higher valuations, AstraZeneca seems to be worthy of a P/E ratio of at least 18.7, which would represent a 25% rise from its current share price.

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Peter Stephens owns shares of AstraZeneca and Prudential. The Motley Fool UK has recommended AstraZeneca. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.