I had around $25K stolen via a skimmed debit card from my Chase checking account (in a few hundred separate transactions). I finally noticed after about 6 weeks; they never did until I told them. This despite the fact that all the fraudulent transactions took place at least 100 miles from my residence, some as far as 2000 miles away. I did get all my money back eventually, but it took a month or two and a ton of back-and-forth in person and on the phone to sort out the bad transactions from the good ones (mostly due to their lack of attention to detail). I stopped using debit cards after that (and started monitoring my daily balance).