Why should a majority of investors be able to amend the convertible notes?

In the event a company needs to amend or waive a provision in the notes, absent a provision that says that the note can be amended or waived with the consent of holders of a majority in interest of the notes, the company has to get every single investor to agree to the amendment or waiver. This ends up being difficult as a practical matter if certain investors are unavailable or refuse to sign an amendment or waiver. Typical situations where a company may want to amend or waive a provision of the note might include extension of the maturity date, changing the terms of the automatic conversion on a qualified equity financing, etc. Majority is measured by the principal amount of the notes. The majority trigger may be set higher to two-thirds or seventy-five percent depending on the situation.