Chase Bank notified customers who used its debit cards at Target stores during the retailer's recent security breach that it was limiting the use of its cards during the busy holiday shopping season.  The new limit affects roughly 2 million accounts, or about 10 percent of Chase debit-card holders. The limits will remain in place temporarily while Chase issues new debit cards to its customers who shopped at a Target store during the timeframe. The bank has made the calculation that it'll be less costly to take the steps it is now taking than deal with the loss of financial and time resources that could come in the event that Target's breach leads to more fraud than anticipated on Chase customer cards.