Questrade I loan my TFSA to my margin account, can I trade TFSA and make purchase stocks, is that reduce my margin account total fund available?

 Yes, you can still trade inside your TFSA normally even when it is linked via Margin Power to your margin account. [1]

💡 How Trading Inside Your TFSA Works

Independent trading: You can buy and sell stocks directly inside your TFSA just like before. [1]
No direct cash block: Normal trades inside your TFSA use the cash or assets inside that specific account.
Collateral value shifts: If you sell or buy stocks in your TFSA, the overall equity value of your TFSA may change, which can indirectly adjust your total combined Margin Power buying power. [1]

📊 Impact on Margin Account Funds

No cash transfer: Linking or trading in the TFSA does not physically move cash out of your TFSA into your margin account. [1]
Buying power changes: If your TFSA stocks go down in value—or if you trade risky assets—your total available buying power in the margin account can decrease because the collateral value drops. [1, 2]
Margin risk: If you already borrowed money in your margin account and your TFSA portfolio drops significantly, you could trigger a margin call where TFSA assets might be affected. [1, 2]