Price shocks in every industry can cause significant concerns about an affected firm's ability to service debt, pay dividends, maintain staff, and meet contractual obligations. How firms behave and how those behaviours affect the firm, both in terms of its firm-specific performance and its competitive performance, is of significant interest to both academics and practitioners. The concerns of a price shock are magnified in the upstream oil and gas industry, where the naturally declining, geographically-fixed assets must be continuously replaced, yet both the financial capabilities of firms and the economic viability of projects are significantly reduced. Such a price shock causes this upstream industry to undergo an innovation trajectory change, where the industry leaves its status quo and enters a rapidly changing environment and where Dynamic Capabilities may become a crucial determinant of the strategies deployed. Non-vertically integrated upstream oil and gas firms are particularly affected by the price shock as they do not have offsetting business units and revenues to mitigate the risks or provide alternative investment opportunities that their vertically integrated counterparts do. This multi-case, theory-building analysis examines the differential behaviours, and effects of those behaviours, of four large non-vertically integrated upstream Canadian oil and gas firms during the 2014 oil price collapse. This study finds a wide range of behavioural combinations, such as how and when these firms used retrenchment, managed their long-term debt and debt governance, used equity issuances, and engaged in acquisitions and divestments. Further, this thesis also finds that each firm’s behaviours affected itself differently concerning changes in production levels, firm structure, and firm-specific financial performance, ultimately leading to changes in their competitive performances. The conclusion of this thesis identifies that two firms possibly deployed Dynamic Capabilities to increase their competitive performance by strategically altering firm direction at the onset of the price shock, while the other two firms only used ad hoc methods or best practices and did not improve their competitive performance. A Dynamic Capabilities subcategory termed Dynamic Response Capabilities is defined and presented.