The deal comes as Hershey doubles down on its efforts to move beyond its chocolate heritage. It is the latest in a string of snack deals, as Big Food looks to reach increasingly mobile diners.
The deal values Amplify at $12 a share, a 71 percent premium to Friday's close. The acquisition could be announced as soon as Monday, the sources said.
The sources, who cautioned it is possible negotiations fall through, requested anonymity because the matter is confidential. Hershey, which has a market capitalization of $24 billion, declined to comment. Amplify, which has a market capitalization of $537 million, could not be immediately reached for comment.
The deal is one of the first big initiatives led by Hershey CEO Michele Buck, who took the seat earlier this year. She was named to the role months after the owner of Reese's rebuffed a takeover bid from Oreo Cookie-maker l.
Buck has spoken openly about plans to expand further into the U.S. snacking category, which IRI pegs at roughly $89 billion. Hershey CFO Patricia Little recently acknowledged in an investor call, "Nothing is as profitable [as our core products]... But we do need to expand our portfolio."
The sweets-maker, which has focused on the term "snackfection" - a blurring of the line between sweet and salty snacks - recently launched Hershey's and Reese's popped snack mix and chocolate dipped pretzels.
Snacks have been a rare point of growth for food companies, as U.S. consumers increasingly favor their food on the go. Among snacks, salty bites such as popcorn and chips reign supreme, beating out candy, cheese and cookies.
Hershey has, like many of its peers, for years sought to dip its toes into the category through a series of small acquisitions. It acquired beef jerky maker Krave Pure Foods in 2015 and the parent of "healthy" chocolate bar brand barkTHINS a year later.
It is difficult though to grow these small brands to a scale at which they can make an impact on a company that last year generated roughly $7.4 billion in sales.
More recently, large food companies have been making bigger bets on snacks, confronted with continued slow sales and an increasingly competitive retail environment. With few large snack brands available to make an impact, those with clout have fetched steep premiums.
On Monday, announced plans to buy for $4.87 billion.
SkinnyPop's parent Amplify went public in 2015 after the brand quickly caught on with with snackers attracted to its sunflower coated kernels. It has since sought to diversify, buying U.K. snack maker Tyrrells for roughly $391 million.
Its stock though has more than halved, as it has struggled to support these acquisitions and the leverage they left behind. Amplify has also faced increased competition and retailers who award scale.