Those are the market rumors that prompted shares in the French drugmaker to jump 3 percent today. The move, if confirmed, would likely be seen as a prelude to an all-out bid. Pfizer may be the world’s biggest drugmaker, but is struggling thanks to generic rivals, patent expirations and lab failures.

Not that Sanofi is such a rosy target. The failure to win FDA approval for the Acomplia diet pill, which was rejected over psychiatric side effects, left the drugmaker saddled with a US sales force with less to do than expected. Moreover, such an acquisition would be a huge deal, given that Sanofi’s market cap is about $117 billion.

Nonetheless, two of Sanofi’s largest shareholders - the Oil company Total and the cosmetics firm L’Oreal, which jointly own about 23 percent of Sanofi’s shares, have previously made it clear they don’t consider their stakes strategic. In fact, Total said in August it would sell its 13 percent stake in Sanofi-Aventis progressively. Although, L’Oreal said last June the sale of its stake of around 10 percent wasn’t imminent and its view hadn’t changed after Sanofi won a US patent trial earlier this year over its blockbuster bloodthinner, Plavix.

Officials at Pfizer, Sanofi, L’Oreal and Total all declined to comment on what they said was market speculation, reports Reuters, which reminds us that talk of Pfizer’s interest in Sanofi isn’t new. The drugmaker was rumored to have approached Total about its stake in Sanofi four years ago, before Sanofi bought Aventis.

“It would seem to make sense from a therapeutic perspective,” Mark Purcell, an analyst at Deutsche Bank, tells Reuters. “The cardiovascular franchise would sit quite nicely with that of Pfizer and the CNS (central nervous system) business fits in with where Pfizer’s research is trying to re-emerge. It makes sense - but it’s just a rumor at the moment and it would be a very large acquisition.”