While no one was paying attention, Minneapolis-based Ability Network has become big business: a large health IT company that processes Medicare payments for health care providers. The privately held firm, which now has a workforce of more than 450, drew an eye-popping $550 million investment in 2014. Mark Pulido, who joined Ability’s board in 2011, was tapped in August to take over for Mark Briggs, who steered the company’s recent growth. Pulido brings deep industry experience with more than three decades of health care leadership. His challenge? To nimbly keep the company on course as it continues to steadily grow.