CO 40bb 3-Bet Jam

Definition

A CO 40bb 3-Bet Jam refers to a player in the cutoff position (CO) going all-in as a three-bet, holding a stack of exactly 40 big blinds (bb). This move is most common in no-limit hold'em tournaments, where stack depths and position heavily influence preflop strategy.

When and Why to Use

At 40bb, the stack is considered deep enough that a standard three-bet to around 9-10bb is typical, but jamming instead introduces unique strategic advantages. The cutoff is a late position, so the CO opener often has a wide range. By jamming, the CO 3-bettor puts maximum pressure on the original raiser, forcing them to either fold or risk their tournament life with a calling range that must be very strong. This move is often employed with a polarized range: strong value hands (e.g., TT+, AQ+) and some bluffs (e.g., suited aces or low pocket pairs) that benefit from fold equity.

Considerations

• Stack Sizes: At 40bb, the jam is not a short-stack shove; it risks a significant portion of chips. The original raiser, if also deep, may call with hands like JJ+ or AK, so the jamming range must be carefully constructed.
• Position: The CO has positional disadvantage against the button but advantage over earlier positions. A jam from CO against an early position open is riskier, as that range is stronger.
• Opponent Tendencies: Against tight players, the jam can steal blinds frequently; against calling stations, it should be mostly value.
• ICM Considerations: In tournaments near the money or final table, jamming 40bb may be suboptimal due to ICM pressure—avoiding marginal spots is key.

Related Terms

• Cutoff (CO): The position one seat right of the button.
• 3-Bet: A re-raise after an initial raise.
• Jam/Shove: An all-in bet.
• Polarized Range: A range containing very strong and weak hands, but no medium-strength ones.
• Fold Equity: The chance that a bet forces opponents to fold.