ERHC as a tradable stock is no more valid than the idea that arbitrage was the reason why the sp was kept down during the stock offering !
One would have to trade 50 000 shares in and out on a differential of .005 to make $250 minus the commissions ! The daily traded volumes would not even come close to supporting this !
I really don't think MM care AT ALL about ERHC with its miniscule volume equating to miniscule $'s. They are likely sitting on the sidelines watching the few traders of this stock and doing NOTHING. No real money to be made or lost for them on this stock at this time. And the MM DO NOT set the bid/ask spread or even get involved unless their is an imbalance. Traders do.