Do repost and rate:
Good till cancelled orders are orders specific to stock trading. They specify that an order has to remain open, even after the market has closed by day-end (Usually all orders are automatically cancelled when the stock market closes).
Some cryptocurrency exchanges may have specific policies regarding open orders with an automatic cancellation after a set period of time (30 days). Placing a GTC order ensures it remains perpetually open on these exchanges.
Pros: Good for traders that want to buy/sell at low/high prices and are not often on the exchange.
Cons: Lockup of liquidity (balance’s funds allocation)
