What happened

Shares of Illumina (ILMN -1.35%) were sinking 9.5% at 11:33 a.m. ET on Friday. The decline came after the company announced the departure of CFO Sam Samad in a press release issued after market close on Thursday.

So what

When a top executive -- especially the CEO or CFO -- unexpectedly leaves a company, it typically raises questions about the reason for the departure. Sometimes, the answers to those questions are legitimate causes for concern.

Illumina's press release didn't provide details about why Samad is stepping down as CFO. However, Quest Diagnostics revealed on Thursday that Samad will become its new CFO. 

Quest Diagnostics is a smaller company than Illumina based on market cap. It's unclear why Samad chose to take what some would view as a step down on the career ladder after serving as Illumina's CFO for five years. 

In the press release announcing Samad's departure, Illumina CEO Francis deSouza praised the "significant contributions" that Samad made during his time at Illumina. Samad will leave the company on July 8, 2022.

Now what

Illumina named Joydeep Goswami, who currently serves as chief strategy and corporate development officer, as its interim CFO. The company plans to conduct a search for a new CFO.

Barring any other revelations about Samad's exit, the pullback in Illumina's shares could present a buying opportunity for investors who believe in the long-term prospects for the genomics stock. The company remains the top player in the genomic-sequencing market. It ended the first quarter with a record backlog. Illumina's GRAIL business also continues to pick up momentum in the liquid biopsy market.