In the first test of investors’ appetite for high-profile IPOs since LinkedIn’s successful public offering last month, Pandora is expected to begin trading Wednesday.

Pandora is offering 14.7 million shares for $10 to $12 per share. The company increased the size of its IPO last week by 43%.

Unlike LinkedIn, though, Pandora is not profitable. The company lost $1.8 million in fiscal 2010 on revenues of $137.8 million and stated in a recent SEC filing, “We expect to incur operating losses on an annual basis through at least fiscal 2012.” Pandora has 34 million active users. Advertising generates 90% of the company’s sales.

Pandora’s public offering is expected to be followed by IPOs for Groupon and Zynga. Groupon has filed its preliminary paperwork for such an offering. Zynga is reportedly close to filing.

[via Bloomberg]