Square IPO to test Dorsey's ability to run two companies

By Heather Somerville SAN FRANCISCO (Reuters) - Mobile payments company Square Inc filed for its long-expected initial public offering on Wednesday in a test of Chief Executive Officer Jack Dorsey's ability to take the company public as he grapples with a turnaround at Twitter Inc. Square's filing on Wednesday comes little more than a week after Twitter appointed Dorsey to head the microblogging site. To address concerns about Dorsey's two jobs, Twitter also on Wednesday named Google Inc executi