Omnicom CEO John Wren told media in Palm Beach that ad spending is "holding up well enough. We haven't seen erosion in clients." But apparently doing "well enough" isn't enough for Omnicom to pay employees their usual bonuses. Wren said ad agency would cut into bonuses, rather than lay off employees. Layoffs or bonus cuts, it's clear that clients may be keeping their accounts with Omnicom, but they aren't spending as much. That's bad news for online advertising, which Wren said accounts for 10 to 15 percent of Omnicom client spending.