Say you check out your account online and notice that your checking account has been charged a really small amount: Ten cents, five cents… even a penny. It might seem odd, but due to the low amount you may simply ignore it.
Don't. Testing out a credit card or checking account by making a small charge is a common tactic some identity thieves use. If the charge goes through, they follow it with much larger purchases or withdrawals. To make you less suspicious, most use a fictitious (yet important and legitimate-sounding) company name as the recipient of the charge.
Here's the bottom line: No matter how small the charge or withdrawal, if you didn't authorize it challenge it immediately.