What does a CEO’s John Hancock say about his or her personality? The larger the signature, the bigger the ego--at least, according to one study. 

And a large ego leads to narcissistic tendencies, according to a recent study released by the Kenan-Flagler School of Business at the University of North Carolina. The study examined CEO signatures on SEC filings to "measure" and "capture the CEO’s narcissism."

Self-admiring CEOs, the study said, are likely to spend more aggressively and carelessly than their more down-to-earth counterparts.

The study said:

In general, the standardized regression coefficients show that the effect of narcissism is roughly as large as the effect of firm size and firm age. Taken together, our results indicate that narcissism has an economically significant impact on firm performance.

Despite this tendency toward poor performance, the study said that narcissistic CEOs are likely to "enjoy higher compensation, both unconditionally and relative to the next highest paid executive at their firm."

But researchers admit that their findings, while intriguing, may have limitations.

Their proxy for narcissism—signature size—could also be influenced by other factors, such as physical characteristics, education and upbringing, and the way the CEO learned to write.

John Paul Osborn, a forensic document examiner at Osborn & Son in New Jersey, goes a step further, saying he believes the entire premise is unscientific.

“This type of assessment is a pseudoscience, often referred to as graphology or graphoanalysis, which may be enjoyable entertainment at the county fair or at parties but has as much meaning as astrology or tealeaf reading according to many people in my field,” he said to Inc. via email.

“It is, in my opinion, both dangerous and unjust to label anyone with traits like narcissism based on something which lacks any real scientific basis,” he added.