It’s symbology has to do with the accumulation of material goods and the dreamer’s relationship with money. To fill the bank indicates self discipline and precaution. To break it could be a warning that you will have an unexpected expense. To lose it, fear of squandering or of ruin.
[1]To dream of a piggy bank symbolizes greediness and missed opportunities. It may also be a sign that you have been acting selfishly, or being overly stubborn.
[2]