The strike has sent parents rushing to find child care, though the impact on businesses has been muted, at least so far. "If this takes more than a week, then there's going to have to be changes," said Brian Battle, director of trading at Performance Trust Capital Partners, a broker-dealer that has about 150 people working in its Chicago office. "You can wing it for a couple of days, but the duration of the work stoppage is what's going to determine our reaction."