I don't have a big company, and there are probably others who can shed more light on this than me, but I think this is one of the most important and least talked about areas of business.
You can be 'making' all kinds of money, but you can make as little as one cash flow mgt mistake and lose it all.
You've got an account flush with cash on the 15th and decide to buy that new piece of eqpt. Then by the end of the month the payment comes due on all of your other materials, but you have a few big customers that are slow in paying. You now have bills to pay and no $$ to pay it with, even though the books say you should be loaded. Big trouble.
I don't really have any kind of formula for managing my $$. But I am very diligent about collecting my $$ from my customers. Make sure your customers pay some $$ up front, and that you collect your final invoice soon after completion (like 15 days or less). I don't buy any big equipment (10k+) until the end of the season (or I wait until the start of the new season), when I know where I really stand financially.