Catalyst supports three order types accessible from the drop-down in the order ticket. Choosing the right one depends on whether speed or price matters more to you.
Buy in dollars (market order)
You enter the dollar amount you want to spend
Contracts are calculated automatically based on available prices
Executes immediately using available liquidity
Final price depends on what is in the order book — may fill across multiple price levels on larger orders
Buy in contracts (market order)
You enter the exact number of contracts you want
Same execution behavior as Buy in dollars — just sized differently
Useful when you want a specific number of contracts rather than a dollar amount
Limit order
You set the exact price you are willing to pay (for buys) or accept (for sells)
Only executes if the market reaches your price
Gives you price control but may not fill if the market never reaches your price
Limit orders have two duration options:
GTC (Good 'Til Canceled) Stays open until it fills or you cancel it. Use when you are willing to wait for your price.
IOC (Immediate or Cancel) Fills immediately at your price if liquidity is available — cancels anything that does not fill right away. Use when you want your price but do not want an open order sitting.
When to use each
Order type | Best when |
Market order (dollars or contracts) | Execution speed matters more than price precision — you want in now |
Limit order | You have a specific price target and are willing to wait (or miss) to get it |
Choosing between a market order and a limit order comes down to one question: do you need to be in the trade right now, or do you need to be in at a specific price? If speed matters, use a market order. If price matters, use a limit order and be prepared for the possibility that it does not fill.