The mercury in 4th house represents property, mother, motherland, heart, happiness, home comforts, vehicles, luxuries in life, throne, and everything that makes a native blessed to be alive. It is called the house of emotions which is ruled by the Moon. Mercury is associated with critical thinking, diplomacy, logic, and reasoning. Mercury in the fourth house represents happiness, thinking, and study. The natives enjoy increased power of concentration when Mercury transits in the fourth house. It can be a favourable placement of Mercury if Mercury is benefic and strong. The placement of Mercury in its own sign that is Gemini or Virgo or in the signs of its friendly planet, Venus and Saturn are considered benefic and strong.
The influence of Mercury in the fourth house in Vedic astrology will make you an extremely imaginative person who dreams up all sorts of unusual ideas and plans. The natives possess a good memory power and tend to retain lots of information as Mercury in 4th house imbibes intelligence in them. They may possess a sharp, tricky, and critical mind at the same time good in calculations. So they can excel as mathematicians, astrologers, or any other field where calculations or tricky ability is needed. They can be more inclined towards subjects related to history, psychology, or politics. also checkout venus in the 9th house