Is Zakat obligatory on the principal circulating capital of 100,000 USD, or only on the profits, knowing that the principal capital is not readily available and requires three months to collect, and that the profits are received every one or two months?

If the money is invested in trade goods, Zakat (definition) is obligatory on both the principal and the profits together, and one-quarter of one-tenth must be disbursed, even if you have to sell part of the goods to pay the Zakat. However, if the money is invested in fixed assets not intended for sale, Zakat is obligatory only on the return (yield) if it reaches the nisab (definition) and a year has passed over it, and one-quarter of one-tenth is to be disbursed from it.