Piggy Bank dream meaning is explained below using 2 different sources. Each interpretation is shown with its source.

Interpretation 1 — Martha Clarke

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.
Source: The Big Dictionary of Dreams Author: Martha Clarke

Interpretation 2 — myjellybean

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.
Source: My Dream Interpretation Author: myjellybean