French drugmaker Sanofi-Aventis has put together about $10 billion in loans for its $18.5 billion bid for U.S. biotech company Genzyme, Bloomberg reported on Friday, citing unnamed sources.

BNP Paribas, JPMorgan Chase and Societe Generale are backing Sanofi's bid, several sources told press representatives earlier this month.

Sanofi Chief Financial Officer Jerome Contamine has said the terms of the financing were attractive and compared favorably to some of the recent acquisition financings in the past 18 months.

The two sides are in a standoff after Genzyme rejected Sanofi's $69 per share bid as inadequate.

Genzyme is seeking an offer of at least $75 a share before serious negotiations could begin, sources have previously told. Separately, a poll showed that analysts estimate Sanofi could buy Genzyme for about $78 a share, or $20.8 billion.

Sanofi wasn't immediately available for comment.