Systematic Investment Plans (SIPs) are monthly investments that go into your selected mutual fund scheme from your bank account. A systematic transfer plan (STP) is where you choose a liquid scheme to park your surplus and then monthly investments are transferred from that scheme to the equity fund of your choice. STPs come in handy when you have got an inflow of a large sum (bonus or maturity of other investments) and you want to invest it in a staggered manner. Remember, the liquid fund and equity fund should be from the same fund house if you wish to opt for STP facility.