Simple & Non-simple Investments

Simple Investment: the NC0 is negative and only one sign change occurs in the net cash flow series. It has a unique IRR if it exists.

Non-simple Investment: more than one sign change occurs in the net cash flow series. It may have multiple IRRs.

Pure & Mixed Investments

Pure investment: NFV(IRR)n are either negative or zero during the project life, with the NC0 being negative. Simple investments will always be pure investments.

Mixed investment: Any of NFV(IRR)n is positive during the project life, with the NC0 being negative. Mixed investment will always be nonsimple investments.