Square Inc, a mobile payments company, is going to set the price for its IPO late Wednesday. Square, run by Twitter Inc. Chief Executive Jack Dorsey, is already valued at $1 billion. Earlier in the month the firm announced the price range for its IPO was $11-$13, giving it a value of $4.2 billion, which was 30% less than in a fundraising round from a year ago. This is one of the steepest valuation discounts since the start of 2014. Other big ones include the 40% discount for Hortonworks Inc, a big ata company, and the 32% discount for Box Inc, a storage firm. Square will sell 25.7 million Class A common share, while a charity created by Dorsey is expected to sell about 1.35 million shares.