NOTE 4. FINANCIAL INSTRUMENTS

Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The fair value hierarchy is based on three levels of inputs that may be used to measure fair value. Level 1 and Level 2 are considered observable and Level 3 is considered unobservable, as follows:

Cash and Cash Equivalents

The Company’s money market funds are categorized as Level 1 within the fair value hierarchy. As of June 30, 2021, the Company’s cash and cash equivalents balances were as follows:

As of December 31, 2020, the Company’s cash and cash equivalents balances were as follows:

Stock Warrants

All of the Company’s outstanding stock warrants are categorized as Level 3 within the fair value hierarchy. Stock warrants have been recorded at their fair value using either a probability weighted expected return model, the Monte Carlo simulation model or the Black-Scholes option-pricing model. These models incorporate contractual terms, maturity, risk-free interest rates and volatility. The value of the Company’s stock warrants would increase if a higher risk-free interest rate was used, and would decrease if a lower risk-free interest rate was used. Similarly, a higher volatility assumption would increase the value of the stock warrants, and a lower volatility assumption would decrease the value of the stock warrants. The development and determination of the unobservable inputs for Level 3 fair value measurements and fair value calculations are the responsibility of the Company’s management with the assistance of a third-party valuation specialist.