Analyst Update: Navistar International Corp, Stone Energy Corporation, and Vonage Holdings Corp.

Analysts are weighing in on truck manufacturer Navistar International Corp (NYSE:NAV), oil-and-gas stock Stone Energy Corporation (NYSE:SGY), and telecom concern Vonage Holdings Corp. (NYSE:VG). Here's a quick roundup of today's brokerage notes on NAV, SGY, and VG.

• NAV has been bombarded with negative analyst attention. The stock saw its rating reduced to "sell" from "hold" at both Wabash National and Stifel, with the latter citing concerns over "potentially weak industry demand." At last check, Navistar International Corp has shed 13% to trade at $11.44, and landed on the short-sale restricted list -- but may have found a foothold at its 100-day moving average. Today's negative analyst attention isn't anything new for NAV, as over two-thirds of covering brokerage firms maintain a "hold" or "strong sell" recommendation toward the stock.

• On the other hand, SGY has jumped over 14% to trade at $5.45 -- yet remains 87.3% lower on a year-to-date basis. Triggering today's upward action was news the company will make a $29 million interest payment on senior notes, thereby avoiding default. Adding fuel to the fire, Ladenburg Thalmann upped its price target to $5 to reflect Stone Energy Corporation's reverse stock split. Short sellers could be smarting amid the stock's sharp rally. Nearly 32% of SGY's float is dedicated to short interest -- and that's after short interest fell 18.6% during the most recent reporting period.

• Similarly, VG has soared 13.3% at $5.37, after Citigroup raised its opinion to "buy" from "neutral," and lifted its price target to $8 from $4.75. Specifically, the brokerage firm said the telecom company has an opportunity to "improve business revenue growth, harvest consumer cash flow, and generate free cash flow yield above Citi's 2017 estimate." Currently, the stock is on track to settle north of its 200-day moving average for the first time since early January. In general, the analyst crowd has taken a glass-half-full approach toward Vonage Holdings Corp., with all seven covering brokerages handing out a "buy" or better endorsement.

For other stocks in analysts' crosshairs, read Analyst Upgrades: GoDaddy Inc, SkyWest, Inc., and Monsanto Company and Analyst Downgrades: Baidu Inc (ADR), Revance Therapeutics Inc, and Chesapeake Energy Corporation.