Call this the year of the credit card breach. From Target to Home Depot, many hundreds of millions of credit cards may have been involved in attacks orchestrated by highly-skilled hackers.

For credit unions, the key question is how best to respond. Know, too, that best practices have been in flux since the Target breach mainly due to the plethora of other breaches that have also occurred.

The reason for that flux may be cost. In February, CUNA estimated that the Target breach alone had cost credit unions $30.6 million, with much of that money spent on card reissuance at a cost per card of a few dollars up to $50 for cards overnighted to members.