SAM (Serviceable Addressable Market): the chunk of TAM your product, languages, distribution channels, and pricing can realistically serve right now.
When Spotify launched its free tier in October 2008, its global TAM was every recorded-music listener on Earth, but its SAM was the seven European countries where it had secured streaming licenses. Adding the US in 2011 took two years of label negotiations, and India did not arrive until 2019. Each expansion was a SAM unlock, not a product launch.
