I once worked at a company which used a money market fund for its cash. That gave them a slightly better return than a bank account. In the end, not sufficiently better to be worth bothering with.
You can get whatever risk profile you want from the stock market in return for less yield. If you can accept two-nines certainty that you won't lose half your money in six months, any broad index fund will do. That would be acceptable for a lot of "modest businesses" which find themselves with "6-7 figures cash reserves". If you need better, you can do fancy things with options, or put a fraction of the money in the bank and invest the rest.
(I am a financial professional, but not in this field, and this is not financial advice)
The US stock market has been ridiculously pumped from the last decade-plus of money printing, I wonder how many people think that's normal.
So if your business is doing well you can avoid putting all your eggs in one basket by investing some cash personally outside the business. And the easiest way is to jus put it into an index fund and then concentrate on your business.
By all means plow a lot of it back into the business, but there’s good reason to pull some out over time as well.
Shares (and all their financial derivatives) are a good hedge for profitable limited companies, because they either go up in value (yay! profit!) or down in value (yay! tax deductable loss rolled over to next year!). So long as the company is otherwise making a profit, shares are actually pretty hard to lose out on.
Also pensions. Most pensions are backed by index funds which are generally related somehow to stocks and shares. If you need to manage a pension fund, you have to pay at least vague attention to the stock market.