Colorado Code
Part 3 - Territorial Applicability and General Rules
§ 4-1-309. Option to Accelerate at Will

A term providing that one party or that party's successor in interest may accelerate payment or performance or require collateral or additional collateral "at will" or when the party "deems itself insecure", or words of similar import, means that the party has power to do so only if that party in good faith believes that the prospect of payment or performance is impaired. The burden of establishing lack of good faith is on the party against which the power has been exercised.
Source: L. 2006: Entire article R&RE, p. 469, § 1, effective September 1.
Editor's note: This section is similar to former § 4-1-208 as it existed prior to 2006.
Source: Former Section 1-208.
Changes from former law: Except for minor stylistic changes, this section is identical to former UCC Section 1-208.

Obviously this section has no application to demand instruments or obligations whose very nature permits call at any time with or without reason. This section applies only to an obligation of payment or performance which in the first instance is due at a future date.