NEW YORK (AP) -- Archipelago Learning Inc. is set to begin trading Friday after its initial public offering raised $103.1 million.

The subscription-based online educational programs provider said in a Securities and Exchange Commission filing that 6.3 million shares of its common stock priced at $16.50 each, near the high end of its expected range of $15 to $17 apiece.

The company sold half the shares and the rest were sold by existing stockholders.

The stock is expected to begin trading on the Nasdaq under the symbol "ARCL."

Dallas-based Archipelago provides Web-based educational testing and study aids to students in kindergarten through 12th grade. Its focus on elementary and middle schools differentiates it from most publicly traded education providers, which offer college-level classes.

Shares of rival K12 Inc., which also offers online learning tools to children, have been choppy this fall as cash-strapped state and local governments cut funding to public schools.

Archipelago's biggest customers are public schools. However, the company's products are priced low enough, analysts say, to fall within a principal's budget and are usually sold at the individual school level, not district-wide.

Even though many schools had less cash this past year, Archipelago earned $6.9 million in the nine months ended Sept. 30, compared with $1 million for all of 2008 and $2.9 million in 2007. Sales rose 46 percent from the first three quarters of last year to $32.7 million.

In its SEC filing, Archipelago said it believes it can grow as more of the 118,000 K-12 schools in the country emphasize student testing and teacher accountability in accord with the federal government's No Child Left Behind Act.

Bank of America Merrill Lynch and William Blair & Co. underwrote the deal. They're entitled to purchase an additional 937,500 shares in the next 30 days.