You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Arsenal_F.C.

Context:
In 1886, Woolwich munitions workers founded the club as Dial Square. In 1913, the club crossed the city to Arsenal Stadium in Highbury. They became Tottenham Hotspur's nearest club, commencing the North London derby. In 2006, they moved to the Emirates Stadium in nearby Holloway. Arsenal earned €435.5m in 2014–15, with the Emirates Stadium generating the highest revenue in world football. Based on social media activity from 2014–15, Arsenal's fanbase is the fifth largest in the world. Forbes estimates the club was worth $1.3 billion in 2015.

Question:
How does Forbe's believe the Arsenal club was worth in 2015?

$1.3 billion