The former cabinet minister will make an announcement on May 16 in Montreal, where he is expected to run in this next fall's mayoral election.
Coderre himself has eagerly fed the speculation and continued to do so Wednesday — telling reporters on Parliament Hill about his plan to deliver "an important message to Montrealers" soon.
''My decision is made,'' he said, adding he can't let the cat out of the bag before May 16 because there are still to be done before the announcement.
''We're just putting the finishing touches on some things,'' he said. ''There's a transition in play.''
Coderre has drawn criticism from opponents who say he should resign his Commons seat instead of spending months fomenting suspense while testing the waters for a mayoral run.
The former immigration minister spoke during Wednesday's question period and used the occasion to raise a subject of particular interest to Montrealers.
Coderre demanded to know what the government is doing to keep the United Nations from moving its civil-aviation headquarters out of Montreal.
Its International Civil Aviation Organization offices in Montreal are the only UN agency headquartered in Canada, and the emirate of Qatar is hoping to lure them away.
The city will elect a new mayor in November.
The last mayor, Gerald Tremblay, quit amid a wave of corruption controversies related to his administration and his interim successor, Michael Applebaum, has said he will not run to keep the title this fall.
If Coderre runs, and barring the entry of another high-profile candidate, the next local mayoral race could carry proxy elements of greater political battles.
While Coderre is a federalist who was involved in the unity battles of recent decades, the opposition at city hall is led by former Parti Quebecois cabinet minister Louise Harel, who was on the opposite side in the 1995 referendum.
The third party is led by Richard Bergeron and has a foothold around the progressive areas that voted for Quebec solidaire provincially and gave the federal NDP its first beachhead in the province with the byelection win of Tom Mulcair in 2007.