In trading FX binary options on brief tenors like 1 hour, I frequently see the FX price bounce right on the expiry boundary, like hourly or 20 minute boundaries.
I would like to figure out if these bounces represent actual trades or just manipulation of the FX price by market makers submitting short spurious bids.
However I don't know where FX prices "come from" (e.g. Reuters feed, Bloomberg). Are there any visible FX exchanges where I can easily see the current bid/ask price stack of open orders for FX and see what has actually been traded versus what is just a posted offer?
Also, what is the minimum lot size of an order needed to move the Reuters feed for EUR/USD for example? I.e. if a market maker is moving the underlying price, how much risk do they take on when putting a bid in the stack?