It has been about a month since the last earnings report for Iron Mountain (IRM). Shares have lost about 1% in that time frame, underperforming the S&P 500.Will the recent negative trend continue leading up to its next earnings release, or is Iron Mountain due for a breakout? Before we dive into how investors and analysts have reacted as of late, let's take a quick look at the most recent earnings report in order to get a better handle on the important drivers. Iron Mountain Tops Q4 FFO Estimates, Misses on RevenuesIron Mountain reported fourth-quarter 2018 normalized FFO of 56 cents per share, beating the Zacks Consensus Estimate of 52 cents. The bottom line also compares favorably with the year-ago reported figureof 53 cents.Results reflect decent organic growth in storage and services revenues. The company has also issued outlook for 2019.Adjusted FFO jumped 25.9% year over year to $194 million.Quarter DetailsRevenues of $1.06 billion missed the Zacks Consensus Estimate of $1.07 billion. However, the reported figure improved 9.9% year over year on a constant-dollar basis, reflecting contributions from recent data-center buyouts.Storage revenues came in at $659 million in the quarter and denoted 9.9% increase on a constant-dollar basis. The company recorded 1.9% organic growth, year over year. In developed markets, storage organic revenue growth came in at 0.9%. In Other International markets, storage organic revenue growth was 4.1% year over year.Service revenues amounted to $402 million in the quarter, indicating an increase of 9.8% on a constant-currency basis. Additionally, it witnessed organic growth of 6.1%, year over year. Service organic revenue growth in developed markets and Other International markets came in at 5.1% and 6.1%, respectively.Adjusted EBITDA margin expanded 100 basis points (bps) to 33.9%. This year-over-year upside was driven by the robust performance in North America Records and Information management (RIM) and Global Data Center, which advanced 60 bps and 2,050 bps, respectively.GuidanceIron Mountain has provided its guidance for 2019. On a constant-dollar basis, the company expects revenues of $4,200-$4,400 million and adjusted FFO to lie between $870 million and $930 million.How Have Estimates Been Moving Since Then?In the past month, investors have witnessed a downward trend in fresh estimates.VGM ScoresAt this time, Iron Mountain has a nice Growth Score of B, though it is lagging a lot on the Momentum Score front with a D. Charting a somewhat similar path, the stock was allocated a grade of C on the value side, putting it in the middle 20% for this investment strategy.Overall, the stock has an aggregate VGM Score of C. If you aren't focused on one strategy, this score is the one you should be interested in.OutlookEstimates have been broadly trending downward for the stock, and the magnitude of this revision indicates a downward shift. Notably, Iron Mountain has a Zacks Rank #3 (Hold). We expect an in-line return from the stock in the next few months.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 Iron Mountain Incorporated (IRM): Free Stock Analysis Report To read this article on Zacks.com click here.