correction: net earnings for oxps ~ $88 million, not 63 as I previously stated
also, another similar company, TRAD (tradestation), has a market cap in the neighborhood of 650 mil for annual earnings of about 34 million.
so it looks to me like a P/E of 20 or so is representative for long term estimates (if market conditions are similar)
all my opinions. I am not a financial expert and this is not trading advice.