Paul Khlebnikov, 41, had walked out of his office late on Friday in north-eastern Moscow when a car pulled up and several shots were fired at him. Khlebnikov, a US citizen of Russian origin, died on his way to hospital.
He was the latest victim of post-Soviet city-centre killings which have struck down officials, businessmen and journalists. News reports said cartridges of two different calibres were found, suggesting two assailants had opened fire.
Forbes, the magazine which tracks the worth of the world's wealthy, started publication in Russia in April and a month later issued a list of Russia's biggest fortunes. Dominated by
oil magnates and metals tycoons, it revealed Moscow to be the city with the world's most billionaires.
The editor of Newsweek's Russian-language edition, Alexander Gordeyev, told Interfax news agency he had rushed to Khlebnikov after the attack and spoke to him as he lay dying.
"I asked Paul several times why he thought this had happened. Paul said he didn't know. He told me several times nothing suspicious had happened to him. He said nothing more about it. He just asked for help."
"I asked Paul several times why he thought this had happened," Gordeyev was quoted as saying. "Paul said he didn't know. He told me several times nothing suspicious had happened to him. He said nothing more about it. He just asked for help."
Interfax quoted others associated with the magazine as saying they had no notion of who might be behind the murder.
"Someone among very tough and powerful people probably didn't like the Forbes project," Leonid Bershidsky, publisher of both Forbes and Newsweek in Russia, told the agency.
Post-Soviet public life has been marked by "contract murders", particularly in the 1990s, of prominent figures singled out because of their business or political activities.
Recent victims have included human rights advocate and member of parliament Galina Starovoitova in 1998, Valentin Tsvetkov, governor of mineral-rich Magadan region in 2002 and liberal politician Sergei Yushenkov last year.
Khlebnikov was editor of the
Russian version of Forbes
Forbes clashed with Berezovsky over Khlebnikov's 2000 book entitled "Godfather of the Kremlin: Boris Berezovsky and the Looting of Russia".
Berezovsky, who was close to Boris Yeltsin, Russia's first post-Soviet president but is now a vocal opponent of Vladimir Putin in exile, was accused in the book of corruption and
funnelling large sums out of Russia. He dropped a libel suit after Forbes withdrew some allegations.
Khlebnikov had worked for Forbes since 1989.
Interviewed after the launch of Russian Forbes, Khlebnikov said some Russian magnates had been angry about the publication.
"Those I spoke to reacted in quite a normal fashion," Khlebnikov told Ekho Moskvy radio.
"But those who were always appearing in the papers, of course, were quite angry at least in public. In private conversations, perhaps they were different about it."