A "N/A" reported in a stock's pricetoearnings ratio (P/E), can mean one of two things. The first, and simplest, would be that there is no data at time of reporting to calculate this ratio. This will be the case with a newly listed company that has yet to release its earnings. The second reason that a stock would report "N/A" as its P/E ratio could be that the number is negative. Negative P/E ratios are mathematically possible, but because they are generally not accepted by the financial community, they are usually reported as "N/A," or not applicable.
The P/E ratio is calculated as the stock's current price divided by its earnings per share (EPS). Obviously, it is not possible for a stock to have a negative price, so the negative P/E ratio comes from the EPS of the company being negative (i.e. net loss). Investors can interpret seeing the "N/A" as the company reporting a net loss, and should be aware they are buying shares of a company that is losing money per share of its stock.
To learn more, see our Understanding the P/E Ratio tutorial or Can a stock have a negative pricetoearnings (P/E) ratio?.
This question was answered by Ayton MacEachern.

Can a stock have a negative pricetoearnings (P/E) ratio?
Yes, a stock can have a negative pricetoearnings ratio (P/E), but it is very unlikely that you will ever see it reported. ... Read Answer >> 
How can the pricetoearnings (P/E) ratio mislead investors?
A low P/E ratio doesn't automatically mean a stock is undervalued, just like a high P/E ratio doesn't necessarily mean it ... Read Answer >> 
Stocks with high P/E ratios can be overpriced. Is a stock with a lower P/E always ...
The short answer? No. The long answer? It depends.The pricetoearnings ratio (P/E ratio) is calculated as a stock's current ... Read Answer >> 
How do I calculate the P/E ratio of a company?
Find out how to calculate this common valuation ratio and what the results can tell you about a company's performance. Read Answer >> 
What does the forward p/e indicate about a company?
Explore the forward price to earnings ratio and learn its significance and how it compares to the traditional price to earnings ... Read Answer >> 
What is the difference between forward p/e and trailing p/e?
Understand the difference between the trailing P/E ratio, which is the standard pricetoearnings calculation, and the forward ... Read Answer >>

Investing
Beware False Signals From The P/E Ratio
The P/E ratio is a simple tool for evaluating a company, but no one ratio can tell the whole story. 
Markets
How Do I Calculate the PriceEarnings Ratio?
If Apple is trading at $108.73 per share, and its trailing twelve months' EPS is $6.45, calculate the P/E ratio as... 
Investing
Is Stock With a Lower P/E Always A Better Choice?
Is a stock with a lower P/E always a better investment than a stock with a higher one? The short answer is no, but it depends on a few things. 
Trading
How To Use The P/E Ratio And PEG To Tell A Stock's Future
While the pricetoearnings ratio is commonly used for assessing stock prices, the price/earningstogrowth ratio offers forecasting advantages that investors need to know. 
Investing
Comparing the P/E, EPS And Earnings Yield
Here are three ratios that help investors value stock returns. 
Investing
Explaining Forward PricetoEarnings Ratio
The estimated P/E of a company is often used to compare current earnings to estimated future earnings. 
Investing
5 MustHave Metrics For Value Investors
These quickanddirty ratios will help you find the most undervalued stocks on the market. 
Investing
Differences Between Forward P/E And Trailing P/E
The most common types of price to earnings ratios are forward P/E and trailing P/E. Find out how they differ and the advantages and drawbacks of each. 
Investing
The 4 Basic Elements Of Stock Value
Investors use these four measures to determine a stock's worth. Find out how to use them. 
Investing
Unlocking The P/E Ratio For Apple
We show you how to compute and analyze the P/E ratio for Apple.

P/E 30 Ratio
The pricetoearnings (P/E) ratio is the valuation ratio of a ... 
PriceEarnings Ratio  P/E Ratio
The PricetoEarnings Ratio or P/E ratio is a ratio for valuing ... 
Forward Price To Earnings  Forward P/E
A measure of the pricetoearnings ratio (P/E) using forecasted ... 
Trailing PriceToEarnings  Trailing P/E
The sum of a company's pricetoearnings, calculated by taking ... 
Ratio Analysis
A ratio analysis is a quantitative analysis of information contained ... 
P/E 10 Ratio
A valuation measure, generally applied to broad equity indices, ...