Calix Inc (NYSE:CALX) shares are tumbling premarket today after the company reported fourth-quarter 2023 results and provided weak guidance.

Revenue of $264.7 million marginally exceeded the consensus of $264.4 million.

Adjusted gross margin rose 250 basis points Y/Y to 54.1%, led by higher platform and increased cloud and managed services revenue. 

The company added 17 new BSPs in the quarter, bringing the total to 56 for the year and increasing the total number of Broadband Service Provider (BSPs) leveraging platform to 1,030.

Adjusted EPS of $0.43 surpassed the consensus of $0.36.

At the end of the year, the company had cash and investments of $220.3 million.

Buyback: The company repurchased $44.0 million worth of stocks in the fourth quarter of 2023 and authorized an additional $100 million to maintain the existing stock repurchase program. 

Outlook: Calix sees first-quarter adjusted EPS of $0.17-$0.23 vs. $0.38 estimate and revenue of $225 million-$231 million vs. consensus of $267.57 million.

The company said its first-quarter outlook incorporates the background and considers a few significant customers in 2023 are pausing their purchases in early 2024 as they re-evaluate their capital expenditures.

Price Action: CALX shares are down 19.55% at $35.68 on the last check Tuesday.