# Overtrading: why fast growth eats cash

> Overtrading in numbers: acquisition is paid today and earned back over months, so a fast growth plan digs a cash hole first.

- Course: [Finance for Product People: From Unit Economics to Business Cases](https://productovi.com/courses/finance-for-product.md)
- Module: Does growth pay for itself?
- Lesson 19/32, ~29 min
- Source: https://productovi.com/courses/finance-for-product/growth-eats-cash

## Leo's growth plan

**Alex Tutor:** You're still on Klasna's product team, and Leo has a growth plan for next year. Today: why fast growth can eat cash even when every customer pays back.

**Leo:** Every family pays back its 4,000 UAH in five months. So growth pays for itself! Next year: 60 new families in January, then 20 more every month.

**Hanna:** Each family pays for itself, eventually. The bank account sees all the families at once, and it sees the ad bills first.

**Sofia:** So the 4,000 leaves in the family's first month, and the contribution trickles in afterwards?

**Alex Tutor:** Exactly. Hanna averaged past cohorts into a planning curve: what one acquired family leaves in each month of its life. 1,200 in the first month, 1,040 in the second, and down from there as families leave.

> **Hanna's planning curve**
>
> | Month of life | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
> |---|---|---|---|---|---|---|---|---|---|---|---|---|
> | Contribution per family | 1,200 | 1,040 | 900 | 800 | 720 | 650 | 590 | 540 | 490 | 450 | 410 | 380 |
>
> UAH per family acquired, averaged over past cohorts. CAC: 4,000 UAH, paid in month 1.

**Alex Tutor:** Add the curve up until it reaches the 4,000 CAC. That is the month a family pays back.

> **Exercise:** Use Hanna's planning curve. In which **month of its life** does the cumulative contribution of one family first reach the 4,000 UAH CAC?

## Steady: 60 families a month

**Alex Tutor:** Now stack the cohorts. First Hanna's steady plan: 60 new families every month. In month 1 the January cohort costs 240,000 and leaves 72,000: −168,000.

**Alex Tutor:** In month 2 the January families are in their second month, 1,040 each, and a new cohort costs another 240,000. The table runs this for both plans.

**Alex Tutor:** Do month 2 by hand once, then the table will make sense.

> **Exercise:** Steady plan: 60 new families every month, CAC 4,000 UAH each. Use Hanna's planning curve. In month 2 of the plan the January cohort is in its second month of life and a new cohort is in its first. How much **contribution** do the two cohorts leave in month 2?

**Dataset (CSV):** [Two twelve-month growth plans: steady and fast](https://productovi.com/datasets/finance-for-product/growth-eats-cash/klasna-growth-plans.csv)

Built from Hanna's planning curve with a 4,000 UAH CAC. Fixed costs are left out: this is the cash of growth alone.

- `plan`: steady (60 new families a month) or fast (60, then +20 a month)
- `month`: Month of the plan, 1–12
- `new_families`: Families acquired that month
- `acquisition_spend_uah`: Ad spend: new families × 4,000 UAH
- `contribution_uah`: Contribution margin from all cohorts acquired so far
- `net_cash_uah`: Contribution minus ad spend that month
- `cumulative_cash_uah`: Running total of net cash since month 1

**Sofia:** For the steady plan, net cash turns positive in month 5, when the first cohort pays back. Before that the total keeps sliding.

**Hanna:** That low point is the cash Klasna must have before the plan starts. Then it climbs: by month 12 the steady plan is 906,000 UAH ahead.

> **Exercise:** Use the dataset (plan = steady: 60 new families every month). What is the **lowest cumulative cash** of the steady plan? Enter it as a negative number.

## Fast: 20 more every month

**Leo:** And my plan?

**Sofia:** Its hole goes down to −672,200 in month 6: twice as deep as the steady plan's, and two months later.

**Cumulative cash of growth, steady vs fast plan**

| Month of the plan | Steady: 60 a month | Fast: +20 a month |
| --- | --- | --- |
| 1 | -168000 | -168000 |
| 2 | -273600 | -329600 |
| 3 | -325200 | -472400 |
| 4 | -328800 | -584400 |
| 5 | -289200 | -654400 |
| 6 | -210600 | -672200 |
| 7 | -96600 | -628400 |
| 8 | 49800 | -514200 |
| 9 | 225600 | -321800 |
| 10 | 428400 | -43800 |
| 11 | 655800 | 326400 |
| 12 | 906000 | 795200 |

*UAH, before fixed costs. Every cohort pays back in month 5 in both plans.*

**Alex Tutor:** Each month the newest cohort is also the biggest. It costs 4,000 per family up front and leaves only 1,200 that month. As long as new spend grows faster than what older cohorts bring back, the hole gets deeper.

**Hanna:** And look at month 12: the fast plan has 795,200, less than the steady plan's 906,000, after spending 8,160,000 on ads instead of 2,880,000.

**Leo:** But with 2,040 new families instead of 720!

**Alex Tutor:** Yes, and that's the point. Most of their contribution is still ahead: growth turns cash today into customers who pay later. The question isn't whether it pays, but whether Klasna can carry the hole until it does.

> **Exercise:** Use the dataset (plan = fast: 60 new families in month 1, then 20 more each month). In which month does the **fast** plan reach its lowest cumulative cash?

**Alex Tutor:** Leo will point at month 12. Read it correctly.

> **Exercise:** At month 12 the fast plan has 795,200 UAH of cumulative cash and 2,040 families acquired; the steady plan has 906,000 and 720 families. Which reading is right?

## Overtrading: payback of a family vs payback of a plan

**Sofia:** So "every family pays back in five months" says nothing about when the whole plan turns cash-positive.

**Alex Tutor:** Right. Payback is a property of one cohort. The plan is a stack of cohorts at different ages, and while it accelerates, the youngest, most expensive ones dominate.

**Hanna:** In the steady plan net cash turns positive in month 5, together with the first cohort. In the fast plan only in month 7.

**Leo:** And if I kept accelerating after month 12?

**Alex Tutor:** Then the hole stays open for longer. A plan that accelerates without end never stops needing cash.

**Alex Tutor:** If the hole is deeper than the cash you have, that's **overtrading**: growing faster than your cash can fund, so a business runs out of money while every customer is profitable. Klasna's fast plan needs 672,200 UAH before it turns cash-positive in month 7.

**Hanna:** Put the difference between the two holes in one number for the board.

> **Exercise:** Use the dataset. Before fixed costs, how much **more cash** does the fast plan need at its lowest point than the steady plan needs at its lowest point?

> **Exercise:** **True or false:** because every cohort pays back in month 5, the fast plan's monthly net cash also turns positive in month 5.

## What drives overtrading: the depth of the cash hole

**Sofia:** What decides how deep the hole gets?

**Alex Tutor:** Three things: how much each new customer costs up front, how quickly they pay it back, and how fast you add new ones. A higher CAC, a slower curve or a steeper ramp all dig deeper.

**Hanna:** And this table leaves out fixed costs. The team, the office and the summer dip need cash too, at the same time.

**Alex Tutor:** Anything that brings cash earlier makes it shallower: keeping more families in their first months, or packages paid up front.

> **Exercise:** Which changes make the cash hole of a growth plan **deeper**?

## Your turn: can we afford it?

**Leo:** Straight answer for the board: can Klasna afford my fast plan?

**Sofia:** It pays in the end, but it needs about twice the cash of the steady plan, and later.

**Hanna:** And it has to be cash we actually have, on top of salaries and the summer.

**Alex Tutor:** Then give Leo the numbers and a condition he can check.

> **Exercise:** Leo asks: "Can Klasna afford the fast plan (60 new families in month 1, then +20 a month)?" Write a short answer (3–5 sentences) with the cash numbers from the dataset, why the hole is deeper even though every family pays back, and what you would require before saying yes.

> **Key ideas**
>
> - Acquisition is paid **up front**; contribution comes back **over months**. A plan that adds customers stacks cohorts at different ages.
> - Steady plan (60 a month, CAC 4,000, payback in month 5): the cash hole bottoms out at **−328,800 UAH** in month 4, net cash turns positive in month 5.
> - Fast plan (+20 a month): the hole is twice as deep, **−672,200** in month 6, and net cash turns positive only in month 7, though every family still pays back in month 5.
> - The hole deepens with a higher CAC, a slower payback curve and a steeper ramp; retention, prepayment and cheaper channels make it shallower.
> - Growth turns cash now into customers later. Ask not only "does it pay?" but "can we fund the hole, on top of fixed costs?" Growing faster than you can fund the hole is **overtrading**.

**Alex Tutor:** Next: the case. Leo wants to double marketing right before exam season, and we have last spring's channel data.

- Previous lesson: [Discounted LTV and CAC payback in cash](https://productovi.com/courses/finance-for-product/ltv-and-cac-payback-in-cash.md)
- Next lesson: [Case: double marketing before exam season?](https://productovi.com/courses/finance-for-product/marketing-budget-case.md)

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