The Rambus Inc. (NASDAQ:RMBS) share price has done very well over the last month, posting an excellent gain of 41%. But the gains over the last month weren't enough to make shareholders whole, as the share price is still down 4.7% in the last twelve months.

Since its price has surged higher, Rambus may be sending very bearish signals at the moment with a price-to-earnings (or "P/E") ratio of 34.9x, since almost half of all companies in the United States have P/E ratios under 18x and even P/E's lower than 11x are not unusual. Nonetheless, we'd need to dig a little deeper to determine if there is a rational basis for the highly elevated P/E.

Rambus hasn't been tracking well recently as its declining earnings compare poorly to other companies, which have seen some growth on average. It might be that many expect the dour earnings performance to recover substantially, which has kept the P/E from collapsing. You'd really hope so, otherwise you're paying a pretty hefty price for no particular reason.

If you'd like to see what analysts are forecasting going forward, you should check out our free report on Rambus.

Is There Enough Growth For Rambus?

There's an inherent assumption that a company should far outperform the market for P/E ratios like Rambus' to be considered reasonable.

Taking a look back first, the company's earnings per share growth last year wasn't something to get excited about as it posted a disappointing decline of 39%. However, a few very strong years before that means that it was still able to grow EPS by an impressive 105,858% in total over the last three years. So we can start by confirming that the company has generally done a very good job of growing earnings over that time, even though it had some hiccups along the way.

Looking ahead now, EPS is anticipated to climb by 19% per annum during the coming three years according to the five analysts following the company. That's shaping up to be materially higher than the 11% per year growth forecast for the broader market.

In light of this, it's understandable that Rambus' P/E sits above the majority of other companies. Apparently shareholders aren't keen to offload something that is potentially eyeing a more prosperous future.

The Final Word

Shares in Rambus have built up some good momentum lately, which has really inflated its P/E. We'd say the price-to-earnings ratio's power isn't primarily as a valuation instrument but rather to gauge current investor sentiment and future expectations.

We've established that Rambus maintains its high P/E on the strength of its forecast growth being higher than the wider market, as expected. At this stage investors feel the potential for a deterioration in earnings isn't great enough to justify a lower P/E ratio. It's hard to see the share price falling strongly in the near future under these circumstances.

Before you settle on your opinion, we've discovered 1 warning sign for Rambus that you should be aware of.

Of course, you might find a fantastic investment by looking at a few good candidates. So take a peek at this free list of companies with a strong growth track record, trading on a low P/E.

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