The ISP launched the review of the account, which has been held by TBWA\London since 2000, following its acquisition by IAC/Interactive Corp.
Fallon's brief includes advertising and an attempt to reposition the Ask Jeeves brand. Work by Fallon is also seen as vital as it attempts to mount a challenge to rivals Google, Yahoo! and MSN.
This latest announcement does not affect Ask Jeeves UK's media planning and buying account, which is handled by Media Planning Group.
Ask Jeeves' US advertising account, which is held by TBWA\Chiat\Day San Francisco, is also understood to be under review. In the US, Ask Jeeves has enjoyed a resurgence in recent months.
According to Nielsen//NetRatings, it is now the fifth-placed internet search brand, with a 77% growth between June and October after it abandoned the "Jeeves" from its web address to become ask.com.
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