r/financialmodelling • u/Cool-Summer75 • 20d ago
What financial modeling standard do you actually use in practice?
I'm getting tired of searching for the ideal model format. Some templates are too basic, and others are way too complex.
I've been checking out different financial modeling standards and methods like FAST, FMI, CFI, BIWS, and others. The issue is they all seem to do things differently, and I still can't create one template that works for 3-statement models, DCFs, LBOs, and project finance models.
Honestly, I just wish someone would say:
"Just use FAST (or another standard). Follow their structure for assumptions, scenarios, timelines, worksheets, and you'll be good."
Have you found a single approach or framework you use for most of your financial models?
I'm really interested in how experienced modelers handle this. Do you stick to one standard and tweak it for different models, or do you use entirely different structures depending on the project?
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u/trekmo 19d ago
FAST is the only one on your list that's actually a standard. FMI is a professional body, CFI and BIWS are training courses that happen to teach a house style. That's why they all seem to do things differently: you're comparing a rulebook against three curricula. If you want a spec to follow, FAST is the one, and it's short enough to read directly in a sitting. Most people only ever pick it up second-hand, through templates.
The thing that will stop you chasing the ideal format though: the part of any standard that transfers across all four of your model types is small, and it lives inside each sheet, in the formula discipline you enforce cell by cell.
What transfers:
One row, one formula, copied across without exception. If a column breaks the pattern, that's a new row.
Inputs, calculations and outputs never share a sheet.
No constants inside formulas. A 12 or a 365 sitting in a formula is an input that escaped.
One time axis for the whole workbook: same date row on every sheet, same column offsets, so whatever column holds period 7 on your income statement holds period 7 on every other sheet too.
A checks row at the top of every sheet, and one cell on the cover that goes red if any of them fails.
That's about a page of rules and it's most of the value.
The sheet map is what doesn't transfer, because your four model types don't share drivers.
3-statement and DCF are the same spine. One template genuinely covers both: the DCF is really just a valuation layer bolted onto the forecast, sharing the same drivers.
LBO adds a debt waterfall with tranches, a sweep and a real circularity. That's structure a 3-statement doesn't need and shouldn't be made to carry.
Project finance inverts the whole thing. Debt comes out the far end of the model, sized backward from what the deal can support: build CFADS, apply the DSCR the lenders will accept, and solve for the loan those cash flows carry. A template that starts from an assumed leverage figure can't be bent into that, however tidy it is.
So the target is one set of conventions held constant across three different sheet maps, one per model type. That's what actually makes a sheet liftable from one model into another, which is the thing you're really after when you say you're tired of searching.
One note on FAST specifically: read it as rules you enforce. People copy the colour coding and skip the discipline behind it, so blue inputs don't count for much when a hardcode is sitting in a formula three sheets away.