Every day in the stock market is a battleground. Battles within company management, between hedge funds and between analysts can violently swing stocks up and down independent of how the broader market trades.For example, take GulfMark Offshore ( GLF), which provides offshore marine services to oil and natural gas companies. Following its strong earnings report on Wednesday, the company received both an analyst upgrade and downgrade. On Thursday, Capital One Southcoast raised its price target on GulfMark to $63 from $62 a share but downgraded shares of the company from buy to hold. Meanwhile, Jefferies raised its price target to $69 from $59 and increased its earnings-per-share outlook for the year to $5.87 from $4.86. Jefferies called the shares "undervalued," noting "continued strength in the global market and the massive demand growth potential in Brazil." It also cited "prospects for further improvements in day rates" as a catalyst to drive shares higher. So who is right? Looking back over the conference call, it seems as if Capital One raised several nonissues of concern about GulfMark's ability to get ships built and delivered in a timely manner. This problem is not specific to GulfMark; it applies to the company's competitors, too. In fact, the lack of available ships gives GulfMark pricing power, which is the main driver for its current growth. Also, raising day rates by 60%-plus in Southeast Asia is more accretive to GulfMark's bottom line. The Jefferies upgrade on GulfMark makes much more sense. Jefferies highlighted the main takeaway from GulfMark's first-quarter conference call: the potential growth in Brazil via contracts with Petrobras ( PBR). This growth has the potential to double earnings in the next few years.