One of the appeals of big-capitalization stocks is their resilience to market sell-offs. On that account, some Big Cap 20 stocks could have done a better job. Losses on the list ranged as much as 4.7% Monday as the broad market tumbled. Most declines were about 2% to 3%. But volume in the 20 stocks was not excessive for most. Some had trading totals that were well below normal, while others had increases of about 40% to 50%.