Shares of On Assignment Inc. rose more than 5 percent the day after it announced healthy results for the fourth quarter. The Calabasas staffing company reported net income of $19.3 million (36 cents a share) for the quarter ended Dec. 31, compared to $20.4 million (38 cents) for the same period a year ago. On an adjusted basis, the company had net income of $40.6 million (76 cents). Revenue increased 31 percent to $578 million. “Our pro forma revenue growth rate for the quarter was 14.4 percent and represented the third straight quarter our pro forma revenue growth rate increased over the preceding quarter,” Chief Executive Peter Dameris said in a statement. “We are entering 2016 with strong momentum which positions us well to continue to report above-market growth rates.” The company also provided guidance for the first quarter of 2016, with revenue between $500 million and $550 million and net income between 28 and 31 cents a share. The company announced results after market close Wednesday. Shares closed Thursday up $1.75 or 5.6 percent to $32.95 on the New York Stock Exchange.