Does creating a market raise my credibility score?

No. Creating a market doesn't add points to your credibility score by itself.

A market starts affecting the score of the person it's about once several people are trading it. From then on, market trust above 50% raises their score and below 50% lowers it, by up to 400 points.
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With the old ETH markets, opening a market gave a small bonus. That bonus doesn't exist on Ethos Trade.
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See How Ethos Trade affects your credibility score.