Shares of Hot Topic Inc. soared Thursday after the company said it will be acquired by private equity firm Sycamore Partners for about $600 million.

The City of Industry retailer’s stock shot up 29 percent to $13.87 after it announced Sycamore would take it private for $14 a share, about 30 percent higher than its closing share price Wednesday.

Before the announcement, the company’s stock had risen more than 22 percent in the last 12 months.

“We are pleased that this transaction will allow us to deliver positive results for our shareholders,” Lisa Harper, Hot Topic’s chief executive, said in a statement.

Within hours of the announcement, securities law firm Tripp Levy PLLC in New York said it was investigating the acquisition and seeking a higher price for Hot Topic shareholders.