The shares were at $19.07, 5.9 percent above their $18 initial public offering price in early trading on the New York Stock Exchange.

Freescale went private in 2006 in a $17.6 billion buyout by a private-equity group led by Blackstone Group LP and including Carlyle Group and TPG Capital LP.

That deal, the biggest leveraged buyout of a technology company on record, has been described by some investors as one of the most unsuccessful because it left Freescale with lots of debt, hurting its ability to compete in the investment-intensive chip business.

Based in Austin, Texas, Freescale makes chips used in cars, mobile phones and e-readers.

The company Wednesday sold 43.5 million shares in its IPO, but priced them at $18, below the filed range of $22 to $24, raising questions about whether investor interest in buyout-backed IPOs may be waning.

Earlier this year, there was a surge of activity as consumer measurement company Nielsen Holdings, hospital operator HCA Holdings Inc, Florida-based BankUnited Inc and pipeline company Kinder Morgan Inc went public.

Citigroup and Deutsche Bank Securities led the underwriters on the Freescale IPO.