In Turkey, three large and decades-old public banks control about a third of the banking sector. These banks were functional to capitalist industrialization in the postwar era and have evolved spontaneously in ways supportive of neoliberalism. These same banks played a key role in stabilizing Turkey amidst the 2008–2009 global crisis. This gives rise to the seeming contradiction of public banks supporting otherwise neoliberal development strategies. The literature around banking and development has largely failed to capture this dynamic, being instead focused on the economics of public versus private banks. As such, the debate has difficulty capturing the multifaceted and conflicting functions of specific banking institutions. By contrast, we suggest that neither private nor public banks are innately superior – rather, it depends. We engage this problematic through the special issue’s debate on institutional function and credibility and the case study of Turkey. As Miyamura’s article in this volume has made an important contribution to the validation of the Credibility Thesis by zooming in on ‘labor’, so will this paper continue the endogenous analysis of the modes of production by focusing on ‘capital’, with its particular reference to state- owned banks in Turkey. From a historical materialist framework, therefore, we argue that Turkey’s public banks have evolved spontaneously, and often unintentionally so, in ways supportive of capitalist development. Turkey’s public banks thus prevail as credible because their institutionalized social content has changed in complex, class- based, and contradictory ways functional to capitalist reproduction. Such credibility is determined not by ownership form nor achieved by intentional, unmediated design, but has evolved historically within different phases of capitalism. Indeed, as financial capitalism intensifies in Turkey, the public banks have become increasingly important to neoliberal reproduction, hence also giving rise to the problem of alternatives.