According to Vedic Astrology, in a horoscope, 12th house indicates:
As far as expenses are concerned, this house is better left alone. Presence or influence of any planet in this house increases the tendency to spend money and the reason or the cause of expenditure depends on the disposition on the planet.
Position of 2nd house lord in 12th is daridra yoga and is considered inauspicious. This is not only an adverse yoga for a getting wealth, it also denotes that there will be expenses. The only exception to this rule is Venus, who is very happy in 12th house according to Uttara Kalamrita. Thus for Aries and Virgo lagna, even though Venus is lord of 2nd house that indicates dhana, it will do well in 12th house. Venus in 12th house also does not check expenses. It ensures that money is spent on luxuries and the person is “happy” about it.
Malefic planets do not tend to do well in this house often making expenditure and making the money wasted for all the wrong reasons.
Other planets (Moon, Mercury, Jupiter, Venus and Ketu) influencing this house ensure that the money is well spent. There are various connotations of “well” here. Essentially it means that the person spending the money will be satisfied with the way money is spent. It could be spent on his family, for his own enjoyment. It could be spent on religious activities, e.g. charity to temples, donations to brahmins etc.
House 11, which represents negation of attributes of the twelfth house is called labhasthana, i.e. house of gains. It has been dealt with in the post on money matters.
Interestingly, it is not the 11th house that governs the willingness to spend money. In Chamatkar Chintamani, it is mentioned that Jupiter or Venus in 3rd house denote a person who does not want to spend money either on others, or on himself. In other words, the person is stingy with money, essentially a miser. Following this logic, we can judge that lords of 2nd or 12th house if situated in 3rd house or under a strong influence of 3rd house lord, will also give results similar to those mentioned for Jupiter and Venus.
Presence of Jupiter in 12th house is said to help a person “accumulate” money. In some sense, this is a combination for misers. A well placed Jupiter will curb the tendency to spend money.