Insperity Inc. NSP delivered fourth-quarter 2017 adjusted earnings of 55 cents per share, which improved 89.7% year over year. The figure also beat the Zacks Consensus Estimate by 9 cents.Insperity’s revenues of $826.5 million increased 13.4% on a year-over-year basis and surpassed the Zacks Consensus Estimate of $814.1 million. Top-line growth can be attributed to 9.8% increase in average number of worksite employees paid per month.2017 at a GlanceIn 2017, earnings were $2.45 per share, up 37% over 2016. Revenues of $3.30 billion increased 12.2% on a year-over-year basis.Average number of worksite employees paid per month increased 10% over 2016. Additionally, worksite employee retention was 85% in 2017. Insperity, Inc. Price, Consensus and EPS Surprise Insperity, Inc. Price, Consensus and EPS Surprise | Insperity, Inc. Quote Insperity’s shares have gained 44.5% in the past year, substantially outperforming the industry’s rally of 19.4%.Operating DetailsInsperity’s gross margin expanded 210 basis points (bps) from the year-ago quarter to 17.3%. Gross profit per worksite employee per month increased 17.3% to $251.Adjusted EBITDA soared 67% year over year to $38.5 million. EBITDA per worksite employee per month surged 40.5% to $52, primarily driven by efficient price management and improved performance in benefits, workers’ compensation and payroll tax areas.Adjusted operating expenses increased 23.2% year over year to $118.4 million. Adjusted operating expenses per worksite employee per month grew 11.8% to $208.Balance Sheet & Share RepurchaseInsperity exited 2017 with adjusted cash, cash equivalents and marketable of $61.1 million compared with $44.9 million as on Dec 31, 2016.The company repurchased roughly 901,000 shares at $38.7 million, issued dividends totaling $65.8 million, including both regular quarterly dividend and the $1.00 per share special dividend declared in December.Capital expenditure of $33.3 million was incurred in 2017 compared with $34 million in the past year.GuidanceFor first-quarter 2018, Insperity projects adjusted earnings in the range of $1.12-$1.16 per share, representing a year-over-year increase of 22-26%.Adjusted EBITDA is anticipated to increase 10-13%, in a range of $69-$71 million. Average worksite employees (WSEs) are expected in a range of 193,500 to 195,300, representing growth of 11-12%.For 2018, Insperity projects adjusted earnings between $2.96 and $3.08 per share implying growth of 21-26%.Adjusted EBITDA is projected to grow 11-15%, in a range of $197-$204 million. Average WSEs are expected to be in the 203,700 to 207,400 bracket, representing growth of 11.5-13.5%.Zacks Rank & Stocks to ConsiderCurrently, Insperity carries a Zacks Rank #3 (Hold).Some better-ranked stocks worth considering are Heidrick & Struggles International HSII, Aspen Technology AZPN and The Ultimate Software Group ULTI, each sporting a Zacks Rank #1 (Strong Buy). You can see the complete list of today’s Zacks #1 Rank stocks here.Long-term earnings growth rate for Heidrick & Struggles International, Aspen Technology and The Ultimate Software Group is projected at 15%, 1.7% and 22.1%, respectively.The Hottest Tech Mega-Trend of AllLast year, it generated $8 billion in global revenues. By 2020, it's predicted to blast through the roof to $47 billion. Famed investor Mark Cuban says it will produce "the world's first trillionaires," but that should still leave plenty of money for regular investors who make the right trades early.See Zacks' 3 Best Stocks to Play This Trend >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Aspen Technology, Inc. (AZPN): Free Stock Analysis Report The Ultimate Software Group, Inc. (ULTI): Free Stock Analysis Report Heidrick & Struggles International, Inc. (HSII): Free Stock Analysis Report Insperity, Inc. (NSP): Free Stock Analysis Report To read this article on Zacks.com click here.