A transactional memory system predicts the outcome of coalescing outermost memory transactions, the coalescing causing committing of memory store data to memory for a first transaction to be done at transaction execution (TX) end of a second transaction, the method comprising. A processor of the transactional memory system determines whether a first plurality of outermost transactions from an associated program that were coalesced experienced an abort, the first plurality of outermost transactions including a first instance of a first transaction. The processor updates a history of the associated program to reflect the results of the determination. The processor coalesces a second plurality of outermost transactions from the associated program, based, at least in part, on the updated history.