The primary limitation of P/E ratio is that it is limited to a moment in time. It gives you an accurate assessment of where one company compares to another at that moment. However, to get a more accurate view of whether a stock is overvalued or undervalued requires knowledge of the anticipated growth rate between the two companies.
For example, let’s use a hypothetical example. Let’s say company ABC has a P/E of 30 and an anticipated growth rate of 50%. Then say that company XYZ has a P/E of 20, and an anticipated growth rate of 5%. Just by looking at the P/E ratio, company ABC looks undervalued. However, if company XYZ is in a mature phase of its business, then company ABC is a better choice for growth-oriented investors.