(Reuters) -Roku ( ROKU ) topped Wall Street estimates for fourth-quarter revenue on Thursday, driven by robust subscriber growth and strong advertising sales.

Shares of the firm rose 9.7% in trading after the bell.

Roku ( ROKU ) has expanded its advertising offerings to small- and medium-sized businesses, leveraging its home screen to diversify revenue streams across sectors.

Brands from retail, automotive and telecom now feature their ads in the platform, enhancing visibility and boosting user engagement. This move allows businesses to tap into Roku's ( ROKU ) extensive user base.

The surge in political ad spending and Roku's ( ROKU ) growing subscriber base have boosted its advertising revenue and audience reach, driving overall growth.

The company's platform segment, which derives revenue from ad sales and subscriptions, grew 25% to $1.04 billion due to advertising activities, particularly from the political vertical.

Ahead of the results, Barton Crockett from Rosenblatt said: "Political advertising on connected TV (CTV) stepped up meaningfully this cycle versus the last cycle, in part because of a big push into the medium by Kamala Harris."  

The company reported revenue of $1.20 billion in the fourth quarter, compared to the analysts' average estimate of $1.15 billion, according to data compiled by LSEG.