So You've Acquired a Company. Now What? A practical guide to the first 100 days, from someone who's been in the book

By Sue Mulligan, Founder & CEO, Agile Advisors

Congratulations. You did it. After months of deal sourcing, due diligence, negotiations, and probably a few sleepless nights, you closed.

Now the real work starts.

I've watched a lot of acquisitions play out over the years, particularly in the entrepreneur-by-acquisition space: the mid-career operators, the private equity-backed buyers, the executives who decided they were done making money for someone else and went out to buy a business of their own. It is an exciting moment. It is also the moment where a lot of people make expensive mistakes.

The first 100 days after an acquisition are not the time to talk strategy, rebrand, or reorganize the org chart. They are the time to understand exactly what you bought. Because until you've done that, you don't actually know yet.

Here's how I think about it.

The First 30 Days: Trust Nothing Until You Verify It

I say this with love. The previous owner was probably not lying to you, but the books you inherited almost certainly have problems in them, and the Quality of Earnings report you relied on during diligence was a snapshot, not a guarantee. Your job in the first 30 days is to verify that what you bought is actually what you think you bought.

Start with cash. Always start with cash.

Build a 12-week cash forecast on day one. You need to know exactly how much cash is coming in, when it's coming in, and what has to go out the door before then. Payroll timing matters more than most buyers realize. Missing a payroll cycle in your first month of ownership is not a great way to introduce yourself to the team.

Reconcile every balance sheet account. Banks, credit cards, accounts payable, accounts receivable, and debt. This is not glamorous work, but here is the thing most people don't know: when you reconcile all your balance sheet accounts, you verify all of your P&L activity at the same time. One exercise, two outcomes. Do not skip it.

Create a P&L you can actually trust. The financials you received during diligence were prepared for the purpose of selling a business. That is a different exercise than running one. Build your own version from the ground up based on what is actually there.

Review every loan agreement. Understand your debt covenants and make sure you are in compliance. This is not something to get to eventually. Covenant violations can have immediate consequences and the last thing you need is a surprise conversation with your lender in month two.

Do a deep dive into revenue. What is recurring and what is one-time? What are the margins on each product or service line? How concentrated is the customer base? If 40% of your revenue is coming from one customer, you need to know that now, not six months from now when that customer doesn't renew.

Make sure customers are being properly invoiced and that outstanding invoices are valid. Inflated or incorrect AR is one of the most common issues we find when we walk into a newly acquired business. It affects your cash position and your reported revenue, and it needs to be cleaned up immediately.

Meet with the sales team. Understand who the customers are, what the terms look like, how renewals work, and what the pipeline actually contains. The people on the ground know things the financials don't tell you.

Check your insurance coverage. Does your existing policy actually cover your new business and your new strategy? Is it in line with your debt covenants? Insurance is one of those things that feels fine until it isn't.

Understand your tax obligations by state and locality and make note of timing. Workers' compensation issues, outstanding employee matters, and benefits renewal dates all need to be on your radar in the first 30 days, not discovered later.

The goal by the end of month one is simple: no surprises you didn't already know about. If there are surprises, and there usually are, better to find them now when you still have options.

Days 30 to 100: Build the Infrastructure to Run the Business

Once you know what you actually own, you can start building the systems to manage it properly.

Clean up the chart of accounts and build a functional P&L. The chart of accounts you inherited was designed for whoever owned this business before you. It was not designed for you. Restructure it so that your P&L tells you something useful: by location, by product line, by functional area, whatever lens matters most for how you intend to run this business.

Set up accruals. Accrual-based accounting gives you a far more accurate picture of the business than cash basis. If the previous owner was running on cash basis, this is the time to make the switch.

Put controls in place with proper segregation of duties. This matters more in a smaller business than people think. You cannot have the same person writing checks and reconciling the bank account. It is not an accusation of anyone. It is just good financial hygiene and it protects everyone.

Build a one-year forecast with scenario modeling. Not an optimistic projection, not a number designed to make someone comfortable. A real forecast with real assumptions that you can defend, with scenarios that show what happens if revenue comes in at 80%, or if you need to hire two people earlier than planned, or if a major customer doesn't renew. Investors and lenders will want this. More importantly, you will need it to make decisions.

Create industry-specific KPIs. Generic metrics are better than nothing. Industry-specific metrics are actually useful. Figure out what the right indicators are for this particular business and start tracking them from day one so you have a baseline.

Build a monthly reporting package for investors and lenders. If you have outside capital involved, they are going to want regular visibility. Build the reporting infrastructure now so it is not a scramble every month.

Do a deep dive into inventory if the business carries it. What is usable, what is dead stock, and what is the plan to reduce waste? Inventory issues are often quietly expensive and they tend to get worse when left alone.

Tighten collections. Review your AR aging and understand what is actually collectible. Put a process in place for follow-up and set clear expectations internally about how collections are handled going forward.

Review payroll and benefits. Are your people getting the right coverage at a competitive price? Renewal timing matters. You do not want to inherit a benefits package that was set up years ago and hasn't been looked at since.

Understand your sales and use tax obligations by state. If the business operates across multiple states, this can get complicated quickly. Get clarity on it now rather than facing a surprise liability down the road.

The Thing Nobody Tells You

The first 100 days are not about transformation. They are about understanding.

The founders and operators I have watched struggle after an acquisition are almost always the ones who came in with a plan they were committed to before they knew what they had. They moved fast and made changes, then found out six months later that the changes they made were based on numbers they couldn't actually trust.

The ones who do it well slow down first. They get into the books, ask a lot of questions, and build the foundation before they build anything on top of it.

You spent months getting to close, so please give yourself 100 days to understand what you bought before you start reinventing it!

The strategy can wait. The financials cannot.

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Sue Mulligan is the Founder & CEO of Agile Advisors, an outsourced accounting and finance firm specializing in venture-backed startups and entrepreneur-led acquisitions. She started the company ten years ago on a soccer field, of course, and has since grown it into a team of 30, predominantly women returning to the workforce. Agile Advisors is based in Chicago.