Valve has updated their policy on game trading in Steam, requiring a one month wait period before giftable games can be traded.
All new games purchased as a gift and placed in the purchaser’s inventory will be untradable for 30 days. The gift may still be gifted at any time. The only change is to trading.
The move is part of an ongoing effort to clamp down on steam key resellers using fraudulent credit cards to buy and quickly distribute keys. Games can still be gifted normally.