I think judicious use of credit is a good strategy for growing your wealth, but when everyone is borrowing money for the same thing, something is up. Not everyone needs a margin account to participate in the stock market, for example.
Last I checked, brokerage margin accounts (in good standing anyway) are not included in FICO scores. Admittedly however, I have no knowledge of if or how a delinquent or otherwise unpaid margin debt may impact.
I would prefer to know (1) The city he as born in, (2) His nickname as a child, and (3) The name of his favorite pet.
Same here (score shot up) but about 10 years later...it happen again and my score plunged. The 2nd time, I just didn't care anymore because I was living in another country by that time. wrbtrader