Portable dialysis machine manufacturer Outset Medical Inc. saw its shares soar after the opening of its Nasdaq IPO. The stock rose as high as $61.60 before closing at $60.68, finishing the day with a market cap of nearly $2.5 billion. Trading under the ticker symbol OM, the company priced 8.95 million of its shares at $27 apiece, upsizing its previously reported plans to offer 7.6 million shares between $22 and $24. The offering is set to close Sept. 17.