Market holds will begin on March 9th, you can avoid holds and protect your account by enabling the Steam Guard Mobile Authenticator now.
What is a trade or market hold?
A hold is a period of time where items are held by Steam before a trade is completed or a Market listing is posted.
Items holds help protect your items
Steam accounts are valuable, especially if they have items worth stealing. If you haven’t protected your account with a physical device (the Steam Guard Mobile Authenticator), a trade hold will give you time to discover your account has been compromised and to prevent your items from leaving your account.
A delay to catch and stop item theft
If a user trading away or selling items hasn’t had their account protected by a Mobile Authenticator for the past 7 days:
Trades: item delivery from completed trades will be delayed by Steam for up to 3 days
Market: starting March 9th, sell listings will be held by Steam before they are posted, for up to 15 days
This provides the user time to cancel any pending transactions they didn’t authorize.
Cancelling trades that are pending or in a trade hold will begin a trading cooldown on your account to prevent any further unauthorized attempts to trade away items. There is no cooldown for cancelling market listings.
Remove the need for item holds
Using a Mobile Authenticator ensures that you and only you can trade or sell your items quickly and securely, so holds are no longer necessary. Increase your account security by getting the Steam Guard Mobile Authenticator for iOS and Android devices.
Read the Steam blog post about account security for a detailed explanation on why we implemented holds.