The maximum order and position sizes are aligned with our risk management policy and current market conditions. We’re reviewing requests to amend the quantities for different instruments daily. If you’d like specific quantities to be reviewed, share the ticker and the name of the company in this thread: Reduction in T212 quantities.
Regarding your second question, the limits differ for each instrument as they depend on the trading volumes, liquidity, and current market conditions. Hence, some instruments have low limits due to their trading low volumes and liquidity. These limits are in place because large orders with illiquid stocks could cause delays, price slippage, or difficulty when trying to unwind positions.