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In finance, a complement refers to a good or service that is used together with another good or service. It’s typically the case that if demand for one increases, demand for its complement will also rise. Conversely, if the price of one increases, demand for both that item and its complement may decrease.


The phonetic spelling of the word “Complement” is /ˈkɒmplɪmənt/.

Key Takeaways

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  1. The complement system is a part of the immune system, playing a key role in innate and adaptive immunity by recognizing and eliminating invading pathogens.
  2. It consists of a number of small proteins found in the blood, generally synthesized by the liver, which work together to remove pathogens from the body.
  3. The complement system gets activated via three pathways: the classical pathway, the lectin pathway, and the alternative pathway. Each pathway leads to a cascade reaction which results in the elimination of pathogens.



In the world of business and finance, the term “complement” is essential as it refers to goods or services that are used together, thereby enhancing their value and demand. Complementary goods promote cross-selling and bundling strategies, stimulating increased consumption and subsequently driving up profits. The concept also helps companies understand market dynamics better, devising strategies to mitigate competition, and identifying opportunities for cooperative marketing. An understanding of complements can influence pricing tactics, product design, promotion, and distribution decisions. Therefore, the idea of ‘complement’ plays a crucial role in strategic development and maintaining a competitive edge in an ever-evolving business environment.


In the realm of finance and business, the term “complement” serves a critical purpose in understanding how certain products or services can affect one another’s demand in the market. Essentially, complementary goods or services are ones that are typically used together or, in other words, where the use of one enhances the use of the other. For instance, printers and printer ink, hot dogs and buns, or cars and gasoline can be considered complementary items. If there’s an increased demand for one, it can positively impact the demand for its complement. Complement goods offer valuable insights to companies when planning strategies for pricing, marketing, and distribution. By recognizing and understanding the dynamics of complement goods, businesses can identify opportunities to increase sales. If the price of one product drops, the demand for its complement may rise, boosting those sales as well. Understanding these relationships also helps firms to anticipate shifts in demand that may arise from changes in the price or availability of complementary goods. Consequently, understanding complements can help companies adapt to market changes more rapidly and effectively.


Complement in the business sense refers to a product or service that is directly related to another product or service and enhances its value. When the demand for one item increases, so does the demand for its complementary good. Here are three real world examples:1. Cars and Fuel: Cars are essentially useless without fuel, so these products are complementary. When a person buys a car, they must also purchase fuel regularly to use the car. As a result, any increase in the demand for cars will also drive up the demand for fuel.2. Smartphones and Mobile Apps: These two are also complementary products. The smartphone provides the platform and the apps provide the utility. You can’t use Uber without both a smartphone and the Uber app. Thereby, the demand for smartphones increases the demand for mobile apps and vice versa.3. Movie Tickets and Popcorn: While you can watch a movie without popcorn and you can eat popcorn without watching a movie, the two are traditionally complementary. The classic movie-going experience usually involves both. Hence, increased sales in movie tickets could potentially lead to an increase in popcorn sales.

Frequently Asked Questions(FAQ)

What is a complement in finance and business?

In finance and business, a complement refers to a good or service that is used in conjunction with another good or service, leading to a higher demand. Typically, an increase in the consumption of one product leads to an increase in the demand for its complement.

Can you give an example of a complement in business terms?

Yes, common examples of complements in business are often found in product pairings such as printers and ink cartridges, or smartphones and app services. If more people start buying printers, the demand for ink cartridges naturally increases.

Does the price of a product affect its complement?

Yes, the price of a product does affect its complement. If the price of a product rises, generally the demand for its complement will decrease. For instance, if the price of smartphones increases, the sales of app services could decrease as a result.

Can a good have more than one complement?

Absolutely, a good can have multiple complements. For instance, coffee can be a complement to sugar, creamer, and even breakfast sandwiches.

How does understanding complements help businesses?

Understanding complements can aid businesses in pricing strategies, marketing strategies, and overall product development. It can also help with projections and forecasts about market changes.

How are complements different from substitutes in business terms?

While complements in business increase in demand together, substitutes are products or services that can replace one another. When the price of one good rises, the demand for its substitute often increases as consumers search for a cheaper alternative.

Related Finance Terms

  • Substitute: This term refers to a product or service that a consumer can use in place of another. If the price of a product increases, the demand for its substitute is likely to rise.
  • Cross-elasticity of demand: This term measures the responsiveness of the quantity demanded for one good in response to a change in the price of another good.
  • Complementary goods: These are goods that are typically used together by consumers. If the price of one falls, the demand for its complementary good is likely to increase.
  • Synergy: This term refers to when the combined value and performance of two companies is greater than the sum of the separate individual parts.
  • Demand curve: It’s a graph showing the relationship between the price of a certain commodity and the amount of it that consumers are willing and able to purchase at that given price.

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