Sharing stock, also known as life stealing, is the action of taking a remaining stock from a teammate while having no more stocks of one's own. This causes the player to respawn with one stock, and removes one stock from a team member. This is initiated, by the defeated player, by pressing Start/Pause in Super Smash Bros. and Super Smash Bros. Melee and A+B starting in Super Smash Bros. Brawl when out of stocks. Naturally, this can only be done in a team stock battle, and it requires that at least one teammate has more than one stock remaining. In both Brawl and SSB4, the announcer will say "Share Stock!" ("Share Player Stock!" in the Japanese version) when this action is performed; in Ultimate, he will instead say "Restocked!".
If a team has multiple living players, the stock will be taken from the player with the lowest-numbered port. If multiple players try to steal a stock simultaneously when there aren’t enough stocks for all of them, port priority determines that the lowest-numbered player gets the stock.
Starting in Super Smash Bros. 4, CPUs will always take a teammate's stock at every opportunity until no more are available. When SSB4 was released, CPUs would take the stock immediately after being KO'd; a later update introduced a realistic delay. In previous games, CPUs never use the share stock function, although players can manually have CPUs share stock in Melee by pressing on a controller connected to the same port as the defeated CPU.
While it may seem like a simple decision, many factors should be taken into account when choosing to share stock. Firstly, it is wise for team members to discuss or ask permission before stealing a stock, not only as it may be considered rude not to do so, but also for strategic purposes. For example, if one were to steal a stock from a teammate with two stocks and a high damage percentage, this would essentially be similar to swapping lives, as that teammate is likely to be KO'd soon afterward. Of course, communication is not always possible during online matches, so sharing stock in these instances may be more of a personal decision.
One should also take the stage into account when determining whether or not to share stock. Large stages like Temple allow partners to survive to much higher damage percentages, while smaller stages like Final Destination tend not to.
In tournament doubles, one of the two players on a team is often designated as the "stock tank", typically whichever is controlling the character with higher survivability and/or better camping. General strategy then revolves around the stock tank playing a defensive role, while the other player plays offensively, borrowing stocks as necessary (as they will be KO'd more often), as being caught in a two-on-one with two stocks is worse than having a two-on-two with one stock each.
The transport glitch is a glitch in Super Smash Bros. Melee. If one team member has lost all of their stocks, the other teammate jumps a little higher to where the character would re-appear after falling. Then, the screen is paused, and the defeated teammate simultaneously shares stock. If performed correctly, the character that was defeated should instantly appear on screen when the game is unpaused.