Google’s stock is down almost 40% from its all-time high recorded last November, wiping about $80 billion from the firm’s market capitalization.

Reports suggest that Google’s paid clicks advertising model may be on the decline.

Google shares traded for $452.15 early Tuesday, down about 7% or $34 from Monday. The stock is down about 39.5% from its all-time high of $747.24, which was hit on November 6, 2007.