An immediately addressable market of >$1 billion should easily support significant growth for most small and medium-sized businesses and will be looked upon favorably by potential buyers.
An immediately addressable market of $500 million-$1 billion should easily support significant growth for most small and medium-sized businesses
An immediately addressable market of $250 million-$500 million should easily support significant growth for most small businesses, but medium-sized businesses may attract more scrutiny if they propose high growth rates in a market of this moderate size.
An immediately addressable market of $100-$250 million is relatively small and willl necessarily limit a buyer's growth aspirations for your company unless you can demonstrate that adjacent markets are readily accessible.
An immediately addressable market of <$100 million is very small. While it is possible to have a terrific, profitable small business in such a small market, buyers will discount your valuation unless you already have a very strong leadership position in your niche with opportunities to break out.