Yahoo Chief Mayer Tarnished by Exiting COO’s $100 Million Golden Parachute?

Think the days of Silicon Valley’s exaggerated golden parachutes are long gone? Think again.

Measured even by the Valley’s wacky standards, the $100 million go-away package that Henrique de Castro, Yahoo’s (YHOO) former chief operating officer, could grab after getting sacked 15 months into the job is astonishing on the one hand, and perhaps a bit obscene on the other.

On the recommendation of its hard-charging chief Marissa Mayer, Yahoo’s board hired de Castro away from Google (GOOG) a little more than a year ago with designs for him to resuscitate the search provider’s ad base. His pay? Nearly $40 million, more than Mayer’s $36 million, and more than twice the money Hewlett-Packard (HPQ) chief Meg Whitman pulls in.

Those figures are startling enough, but according to executive pay specialist Equilar, it could cost Yahoo more than $100 million in cash and stock to clear its decks of de Castro. That’s right, a severance package valued at one-hundred-million-dollars—for 15 months work.

Could de Castro’s failed, expensive and abbreviated tenure at Yahoo bruise Mayer’s reputation a bit as a business whiz? Maybe. It was she who recommended him to Yahoo’s board and she who ultimately determined the company could best grow without him, as announced internally last week.

So far, de Castro already has pocketed some $45 million in cash and stock, and he stands to gain up to another $65 million in severance pay and stock—a boost that owes to Yahoo’s improved share price in the past year, according to Aaron Boyd, Equilar’s governance research director, in speaking to the San Jose Mercury News.

It’s not as though Yahoo doesn’t already have a colorful history of generous severance packages, although none approach the beneficence of de Castro’s deal, with the most obvious examples by far for higher-ranking executives. For example, in September 2011, former Yahoo chief Carol Bartz received $3 million in severance and about $477,000 in cash for her two years on the job. And, in May 2012, Scott Thompson was fired from his Yahoo helm after a resume-padding scandal, yet walked away with $1.5 million in cash and $5.3 million in stock.

Yahoo certainly is in good company in paying out exorbitant golden parachutes. There are many examples and here’s but two: In 2011, HP gave departing chief Leo Apotheker $9.6 million in severance and $3.6 million in stock for his one year on the job; and, a year earlier, former chief Mark Hurd exited with a package valued at up to $50 million.

A Yahoo spokeswoman said the company had nothing more to say about de Castro, who departed the premises Jan. 16.