Can I get commission about $100k from Europe Company Finance, Investments

Do you have the agreement in writing from the company responsible to pay the commission? Had a friend of mine who did the same thing in a different industry but his commission was worth millions. Unfortunately a good number of the details weren't in a complete writing even though there were emails as to the agreement and more. It was a brutal litigation that finally ended up being settled after costing my colleague a significant amount of money.

Anyway... the tax question. Of course you'd pay tax if you earned income. The IRS magic words you learn on day one of any tax law class or accounting education is the definition of Gross Income. You'd easily fit within the U.S. Code that defines gross income. It's up to you whether you will report the payment as "earned income" and not the responsibility of these foreign companies to send tax documentation to the IRS. But should you not report the income and you get audited and your bank statements reviewed, be prepared to have a good answer.

26 U.S. Code § 61 - Gross income defined

(a) General definition
Except as otherwise provided in this subtitle, gross income means all income from whatever source derived, including (but not limited to) the following items:
(1) Compensation for services, including fees, commissions, fringe benefits, and similar items;
(2) Gross income derived from business;
(3) Gains derived from dealings in property;
(4) Interest;
(5) Rents;
(6) Royalties;
(7) Dividends;
(8) Alimony and separate maintenance payments;
(9) Annuities;
(10) Income from life insurance and endowment contracts;
(11) Pensions;
(12) Income from discharge of indebtedness;
(13) Distributive share of partnership gross income;
(14) Income in respect of a decedent; and
(15) Income from an interest in an estate or trust.