1. The right for an investor to buy more stock later on to maintain their same level of ownership in a company.
2. The right to say “Ok… I’m going to throw in a little more.”
Example sentence: Holy crapola, Jonny– this electric water bottle company I invested in is really taking off! I’m so relieved I have pro-rata rights and can invest a few more thousand this round and maintain my .2% ownership in SunSipz.