During the reigns of Charles V and Philip II Habsburg, the Spanish Empire had to declare bankruptcy several times. What were the consequences of these events? Did, for example, some of their assets get seized by the bankers, or something like that? Despite the financial troubles, the Spanish Empire survived and grow for several more centuries.
The huge debt inherited from his father, Charles V (Charles I of Spain), had to be renegotiated with bankers several times. Thus, a system of bonds was created in which bankers accepted to receive the interests only. The principal, however, was never returned and the interests kept on growing. This system of bonds was the first in history, by the way.
The main creditor was the Fugger family, a German banking family, but they were never paid the whole amount and went equally through financial difficulties. With them, many members of the nobility of the Netherlands.
According to Reinhart and Rogoff (2008), Spain has gone bankrupt 13 times: "Spain’s defaults establish a record that remains as yet unbroken. Indeed, Spain managed to default seven times in the nineteenth century alone, after having defaulted six times in the preceding three centuries." Sad record.
One important consequence of repeated Spanish bankruptcies was that the modern Netherlands won its war of independence from Spain. It may have (years later), led to the successful secession of Portugal in 1640 as well. In any event, they marked the decline of the Spanish empire, and its eventual withdrawal (in the 19th century) from the affairs of (central) Europe.
Since I was just looking up information in David Graeber's Debt: The First 5,000 Years in the context of another question, I can contribute a quote from that source that confirms part of what @fledermaus has already indicated:
Charles V was continuously in debt, and when his son Philip II – his armies fighting on three different fronts – attempted the old Medieval trick of defaulting, all his creditors, from the Genoese Bank of St. George to the German Fuggers and Welsers, closed ranks to insist that he would receive no further loans until he started honoring his commitments. (Some did go bankrupt – for instance, one branch of the Fuggers. But this was surprisingly rare.)