Multi-Entity Expense Billing at PE Scale: Why Generic ERPs Break Down as Your Fund Count Grows

What the Billing Structure Actually Looks Like

The management company’s expense billing process involves more parties and more moving parts than it first appears. The table below shows how that complexity typically evolves as fund count grows.

Why Spreadsheets Stop Working at Scale

At one or two funds, generating an invoice for each fund and portfolio company from an Excel template is a reasonable process. The counterparty list is short. The allocation methodology is relatively simple. One person can own it.

The billing process doesn’t scale linearly. Each new fund adds not just one more counterparty, but another layer of allocation complexity. Some expenses are shared evenly across participating funds. Others are allocated based on deal participation, the specific beneficiaries of the expense, or methodologies defined in the governing agreements. Co-investment vehicles, SPVs, and parallel funds often have their own reimbursement provisions as well. As the management company’s expense base grows alongside its fund count, the spreadsheet that once tracked three relationships is now tracking fifteen, each with its own allocation logic and supporting documentation.

Three failure modes become increasingly common as that complexity compounds:

• Reconciliation errors: when an invoice is disputed or an allocation needs to be adjusted, tracing the error back through a multi-tab spreadsheet is a manual investigation. There’s no audit trail built into the process: only the spreadsheet itself.
• Version control: billing spreadsheets touched by multiple people across multiple review cycles accumulate inconsistencies. When two people are working from different versions of the model, the numbers they are working from are already in conflict.
• Audit exposure: for RIA firms operating under SEC oversight, expense allocation methodology and documentation are subject to examination. A process that lives in spreadsheets and Word documents is difficult to defend. The methodology exists, but it is embedded in formulas and logic that an examiner can’t easily verify.

The Methodology Problem is Harder to Solve Than it Looks

The allocation methodology is what makes the tracking problem so difficult to manage in a spreadsheet. Management fee terms vary by fund. Expense allocation percentages can be based on AUM or fund size, which means they change as capital is deployed or raised. Some expense categories are allocated to all funds. Others are specific to individual portfolio companies. Co-investment vehicles may have negotiated carve-outs.

In a well-built ERP, the process of identifying billable expenses, generating invoices, and tracking what’s been billed versus what’s still outstanding is managed by the system rather than assembled manually each cycle. The invoice exists in the system. Every expense is tracked as billable, billed, or outstanding in the system rather than maintained in a separate spreadsheet.

In a spreadsheet-based process, the allocation rules exist only in the model. When a methodology changes (a new fund closes with different terms, or a portfolio company’s reimbursement scope is renegotiated), someone has to update the model manually and verify that the change has been applied correctly across every subsequent calculation. Over time, those manual updates accumulate. The model reflects years of decisions made by different people under different circumstances. Auditing that model becomes a significant undertaking.

What A System Built for This Changes

Firms that have made this move describe the same shift: billing becomes a process the system runs, not one the team constructs each cycle.
Intercompany billing flows from the management company to the receiving entity through the system rather than through manually constructed invoices. Billable expenses are tracked in the system: what’s outstanding, what’s been invoiced, and what’s been paid and reconciled. The audit trail is built in: every invoice has a documented record and a clear line back to the underlying expenses.

For RIA firms, that audit trail is a compliance requirement. The ability to demonstrate to an examiner exactly how every expense was allocated, with supporting transaction records, is something a spreadsheet-based process can’t provide. For firms approaching registration, building the infrastructure before an examination is on the horizon is the lower-risk path.

The Scale Question

The billing complexity described here doesn’t appear suddenly. The management company adds a fund, then another. Each one seems manageable. The spreadsheet grows and the reconciliation takes a bit longer.

The inflection point most PE management companies hit is when the cost of maintaining the process, in time, audit risk, and key-person dependency, starts to outweigh the perceived cost of changing it. The firms we work with that reach this point tend to arrive at the same conclusion: the billing process needs to live in the system, not around it.

Sage Intacct handles intercompany billing and billable expense management at the system level. Invoice creation, status tracking across counterparties, and the audit trail between expense and invoice are built into the process rather than managed through spreadsheets. For RIA firms and those approaching registration, that infrastructure isn’t optional: it is what an examiner expects to see.

At Madken Advisors, we specialize in Sage Intacct implementations built specifically for PE management companies, configured around fund structures, multi-entity billing, and LP reporting from the start. If you want to understand where your firm stands before making that decision, the PE Back-Office Maturity Assessment will give you a clear picture of where you are and what modernization at your stage typically looks like.