Are there limits to position size?

For FX pairs: 

The liquidity on GBPAUD, GBPNZD, and USDCNH has been less reliable which has resulted in periodic price gapping in these pairs. In an effort to mitigate customer losses Friedberg Direct instituted a 200K maximum order size specifically for these pairs on Trading Station accounts. Traders may use multiple orders to build exposure of more than 200k. For those who are price sensitive the Market or Entry Range orders may be used to communicate the range of prices in pips with which they are comfortable to the system for execution.

All other Forex pairs have a max trade size of 50 Million units per click. 

For CFD symbols: 

The Max trade size for CFDs will differ per CFD symbol. To check the Max trade size for a specific CFD symbol, please view our CFD product guide.