Shares of PayPal surged sharply on Wednesday following a joint bid from payment processing company Stripe and private equity firm Advent International to acquire the digital payments pioneer for more than $53 billion. The proposed offer values PayPal at $60.50 per share, representing a premium of roughly 28 percent over the company’s closing price of $47.37 on Tuesday.

The acquisition offer, submitted earlier this month, is reportedly backed by approximately $50 billion in committed bank financing. Under the terms of the proposal, Stripe and Advent would each hold an equal stake in PayPal, maintaining the company as a unified business rather than breaking up its operations or selling off assets.

PayPal, which emerged in the late 1990s and played a foundational role in mainstreaming online payments, would be combined with Stripe, a fintech firm that developed later, focusing on providing payment-processing software and financial infrastructure to internet-based businesses. The deal would bring together two firms that defined different stages of the internet economy.

Despite the strong market reaction—PayPal shares rose more than 16 percent during Wednesday’s trading—the stock price remained below the suggested offer. This reflects the absence of an official agreement, as PayPal has yet to respond publicly to the proposal. Stripe and Advent are reportedly seeking to advance discussions, but all parties have declined to comment.

The formal offer follows an initial approach made in early April, though no assurances have been given that the negotiations will result in a completed transaction.