As Snap Inc. prepares to price its initial public offering, fear of missing out on the deal appears to be one of investors’ biggest concerns.

The parent of the popular disappearing-message app Snapchat is on track to price its initial public offering above its target of $14 to $16 a share, people familiar with the offering said. At $17 or $18, where some of the people said the deal is expected to price, the company would be valued at as much as $25 billion.

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