according to coinmarketcap, ARB token started trading at $11.14...
Do you personally know someone who was able to sell ARB at a price close to $10? By the time the price was trading at this level, no one had yet been able to get their airdrop and, accordingly, only those coins that were provided by the project as liquidity security were traded on the exchanges.
We have makishart who sold at $7, I'm sure there ought to be people who sold it at even higher price.
There were single sided liquidity pools available and people had filled it with millions before the launch of arb. I am not aware of arbitrum project filling pool, there was no need for it.
I claimed it manually through arbscan. It was working when the main site down due to the so many traffics that came at the same time. I have sold mine @$7. People who didn't know how to claim by interacted with contract unable to sell their token as high price.