DTAS 2

Here's the reason DTAS falling this morning.

• WR Hambrecht downgraded the marketing services company to hold from buy, citing concerns over the potential loss of American Express (AXP : American Express Company News , chart, profile, more ) as a customer. "Our recent channel checks have confirmed that American Express is seeking ideas from competitive agencies for its commercial card advertising and marketing business currently held by Digitas," said Analyst Denise Garcia in a note to clients. She said that while it's not certain that Digitas will lose the business, the news could still "weigh heavily" on the stock, given that American Express business represented 26% of Digitas revenue over the last year.

The potential loss of such large customer makes it a bit speculative at this point. Caution is required.