The SIP Book
The industry's monthly recurring SIP inflow — sticky, predictable AUM that keeps coming regardless of the market. The CASA / float analogue.
Why you care
Zoom out from one investor's SIP to the whole industry and you get the SIP book: the total recurring SIP money arriving every single month, on standing instruction. It's sticky — people rarely cancel SIPs, even in a crash. That makes it the closest thing a fund house has to a bank's CASA or an insurer's float: other people's money that just keeps coming.
Run the numbers
Monthly SIP inflows run around ₹31,000 crore (illustrative — verify AMFI). That much fresh money arrives whether the market is up or down, because it's automated. So even in a bad month when spooked investors pull lump sums out, the SIP book keeps buying, which steadies the whole industry's flows.
Where this goes
Why you care
The SIP book is the aggregate of all the recurring SIP instalments flowing into the mutual fund industry each month. Where a single SIP is one person's monthly habit, the SIP book is that habit at national scale. It's a large, standing river of money that arrives automatically, month after month, largely independent of what the market did that week.
Its importance is its stickiness, and that's what makes it the funds version of a bank's CASA deposits or a general insurer's float. All three are the same underlying prize: other people's money that keeps coming, cheaply and predictably, and funds the base of the business. Investors rarely cancel SIPs even when markets fall, partly through inertia and partly through the discipline the mechanism instils, so the SIP book keeps buying through exactly the downturns when discretionary lump-sum money flees. For an AMC that means a reliable, growing base of assets to earn its fee on. For the market it means a steady domestic bid that has, in recent years, cushioned falls that foreign selling would once have deepened. It is the single most important structural change in Indian fund flows.
Run the numbers
Picture a bad month: the market drops sharply and nervous investors redeem ₹15,000 crore of lump-sum holdings (illustrative). What stops the industry's assets from collapsing?
- The SIP book delivers roughly ₹31,000 crore of fresh, automated money that same month, regardless of the fall.
- Net of the ₹15,000 crore that left, flows are still comfortably positive.
The redemptions were a decision; the SIP inflow was a standing instruction, and standing instructions don't panic. That asymmetry — discretionary money flees, recurring money stays — is why the SIP book behaves like a bank's low-cost deposit base: it's the ballast that keeps the ship steady when sentiment turns.
Where this goes
The SIP book is what makes AUM durable rather than fickle — a base that keeps growing even through market falls. It is the sticky core of net flows, the component that stays positive when lump-sum money is leaving. And it completes a cross-vertical pattern worth holding onto: the SIP book is to a fund house what CASA is to a bank and float is to an insurer. It's the quiet, sticky pool of other people's money that everything else is built on top of.