Debt, loans and such money matters are seen from sixth house in a horoscope.
6th is a malefic house in a horoscope. Location of a planet in the sixth house is considered a bad placement. Similarly, placement of 6th house lord in any other auspicious house is considered bad for the house. The only good placement for 6th lord is in one of the dusthana houses that cause veepareeta raja yoga. Association of 6th house and its lord with malefics results in Harsha yoga.
As 6th house is a dusthana, it needs to be weaker in the chart for good results. Hence a strong 6th house will lead to debts and loans. An exalted 6th lord, in a good position in horoscope, vargottama, etc. are all such indications of a strong planet.
Such a planet should not be associated with 11th and 2nd house in the kundali at all, because it does not allow for wealth accumulation due to loans. The entire money that a person earns goes in servicing these loans. These are daridra or nirdhana (i.e. poverty) yogas, described in this blog in the appropriate blog post.
The main problem that the current society has is that well earning members of the society take huge loans and are not able to repay the loans. 6th house indicates loans, but then it does not govern other money matters in astrology, especially expenses (governed by 12th house in the horoscope) and the ability to make and accumulate money (11th and 2nd house in the kundali). 6th and 12th house lord in a horoscope should not be stronger than 2nd and 11th houses and should not be associated with them.
Debt/loans by itself are not a problem. The problems we have with not controlling expenses and taking too much loan is the real problem. If 6th house/lord is strong in the horoscope, and other dhana yoga elements are also strong, then the person is fully capable of paying off the loans. We are just talking about debt in this case, not really bankruptcy that will be linked with the daridra yogas.
This is an example chart where there is a lack of debt as the 6th house, its lord are in check by Saturn and Mars.
Incidentally, 6th house is also is responsible for diseases also. The same combination in the chart that shows absence of debt also shows health problems with diseases in abdomen area.