Utilize your financial knowledge, give your answer or opinion to the input question or subject . Answer format is not limited.

Why does my bank suddenly need to know where my money comes from?
Banks have a financial, and regulational duty called "Know your customer", established to avoid a number of historical problems occurring again, such as money laundering, terrorism financing, fraud, etc. Thanks to the scale, and scope of the problem (millions of customers, billions of transactions a day), the way they're handling this usually involves fuzzy logics matching, looking for irregular patterns, problem escalation, and other warning signs. When exceeding some pre-set limit, these signal clues are then filtered, and passed on for human inspection. Needless to say, these algorithms are not perfect, although, thanks to financial pressure, they are improving. In order to understand why your trading account has been suspended, it's useful to look at the incentives: false positives -suspending your trade, and assuming you guilty until proven otherwise- could cost them merely your LTV (lifetime value of customer -how much your business brings in as profit); while false negatives -not catching you while engaging in activities listed above- might cost them multi-month investigations, penalties, and court.  Ultimately, this isn't against you. I've been with the bank for 15 years and the money in the accounts has been very slowly accumulated via direct-deposit paychecks over that time. From this I gather the most likely explanation, is that you've hit somekind of account threshold, that the average credit-happy customers usually do not exceed, which triggered a routine checkup. How do you deal with it? Practice puppetry! There is only one way to survive angry customers emotionally: you have to realize that they’re not angry at you; they’re angry at your business, and you just happen to be a convenient representative of that business. And since they’re treating you like a puppet, an iconic stand-in for the real business, you need to treat yourself as a puppet, too. Pretend you’re a puppeteer. The customer is yelling at the puppet. They’re not yelling at you. They’re angry with the puppet. Your job is to figure out, “gosh, what can I make the puppet say that will make this person a happy customer?”  In an investigation case, go with boredom: The puppet doesn't care, have no feelings, and is eternally patient. Figure out what are the most likely words that will have the matter "mentally resolved" from the investigator's point of view, tell them what they have to hear, and you'll have case closed in no time. Hope this helps.