Mayer's pay package is made up of $1 million in annual salary, as much as $2 million in an annual bonus, and $42 million in stock options and other awards, as well as $14 million in "make whole restricted options" for forfeiture of compensation from Google.
Also, by including some stock grants, Mayer could earn up to a total of $20 million a year, or up to $100 million over five years, a Yahoo spokeswoman told Reuters.
As the first female Google engineer and one of its earliest employees, Mayer's net worth is already estimated to be as much as $300 million.
Yahoo's hiring of Mayer as CEO from Google earlier this week caught analysts and investors by surprise. Mayer, 37, edged out presumed front-runner and acting CEO Ross Levinsohn to become Yahoo's third CEO in a year.
Industry observers believe Mayer's selection over Levinsohn is a signal that Yahoo is likely to renew its focus on Web technology and products rather than beefing up online content.
Her appointment caps a tumultuous year at Yahoo. In May, Scott Thompson resigned as CEO after less than 6 months in the job after a controversy over his academic credentials. Thompson replaced the controversial Carol Bartz, who was fired in September after failing to revitalize Yahoo.
Thompson's total compensation at hire was valued at $27 million. He got no severance but was able to keep the $7 million in compensation he got for leaving Paypal. Bartz got more than $10 million in severance when she was fired last year.
A self-described "geek" with a master's degree in computer science from Stanford, Mayer started as CEO on Tuesday, the same day Yahoo announced weak financial results, with flat net revenue and a slight decline in second-quarter profit.
Although she was on the company's sprawling Sunnyvale, Calif, campus, she did not participate in its earnings call. Levinsohn was also absent from the call, which was led by Yahoo's Chief Financial Officer Tim Morse.
Mayer joins Yahoo as something of a celebrity, having already established herself as one of Silicon Valley's leading women, both inside and outside of the office. She is known for her love of fashion and regularly appears on the society pages for hosting parties.
In 2009 she married real estate investor Zachary Bogue --Mayer tweeted that the couple expects their first child, a boy, in October.
Despite its leadership upheaval, Yahoo remains one of the world's most popular websites, with more than 700 million monthly visitors, according to the company.
But revenue growth has stalled amid an industry wide decline in online display advertising prices and competition from Facebook and Google.