Square Inc IPO to value payments startup at up to $4.2 billion

(Reuters) - Mobile payments company Square Inc, headed by Twitter Inc Chief Executive Jack Dorsey, said it expects its initial public offering to price at between $11 and $13 per share, valuing the company at up to $4.2 billion. "I'd argue that this company is simply not ready to go public yet, even at significant discount from their last valuation", said Brian Hamilton, chairman of private company analysis firm Sageworks. Startups such as Square and Stripe have given industry leaders such as Pa