Because it has money in the bank, and it wants to invest it into growth.

Let's put it this way: if 9 people can only produce enough revenue to pay for themselves, it would be risky to take on a new large client if doing so required an upfront investment that completely depleted your cash reserves.

If things went south and you couldn't capitalize on your investment, you'd have no way to fund a pivot or a recovery strategy. If taking a new client only required a 10th of your bank and things went bad, it would still hurt but you'd have some breathing room. A new hire poses a similar risk.