The value of Amazon's investments in Anthropic have soared. Amazon has agreed to invest $8 billion in Anthropic so far.Anthropic and Amazon have a close partnership that includes an arrangement to use AWS's AI chips.Amazon is seeing massive gains from its investment in Anthropic.The cloud giant estimated the fair value of its stake in Anthropic at $14 billion at the end of December, according to a recent regulatory filing. That's up from $8 billion, the filing shows. That means Amazon's investm...