GENEVA (AP) — Swiss pharmaceutical giant Roche has extended its buyout offer for U.S. diagnostics company Illumina until March 23.

Roche’s offer of $44.50 per share had previously been due to expire Feb. 24.

The Basel-based company said Monday that it is still offering the same price for Illumina shares, valuing the buyout at $5.7 billion.

Investors had expected Roche to increase the bid, which Illumina’s board has rejected the offer as “grossly inadequate.”