Voluntary Accumulation Plan

An investment method where a retail investor periodically invests (at their discretion) relatively small amounts of funds into a mutual fund, building a comparatively large position over an extended period.

Investopedia Says:
By investing savings into a mutual fund gradually over time with a voluntary accumulation plan, an investor is able to build a large investment at their own pace, since their contributions are voluntary (although common practice is to invest a fixed amount at specified intervals). By spreading their contributions over a period of time, investors reap the benefits of dollar-cost averaging, as their fixed dollar amount contributions will buy more shares of a mutual fund when its price is low than when it is high.

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Plan subscribed to by a Mutual Fund shareholder to accumulate shares in that fund on a regular basis over time. The amount of money to be put into the fund and the intervals at which it is to be invested are at the discretion of the shareholder. A plan that invests a set amount on a regular schedule is called a dollar cost averaging plan or Constant Dollar Plan.