The intellectual property of a business consists of the sum of all things a company stands for with all the intangible assets it has developed over the years such as text, graphics, videos, labels, manuals, product and service designs, recipes, research and development and much more. Things are much simpler on single line outputs as happens in the work of painters, authors, photographers, videographers, graphic designers, film makers, TV shows creators, music composers, lyricists, poets and similar professionals were copyright is generated on every original work.
A marketing agency that operates on the highest professional level should be very cautious on clients intellectual rights and totally respect the corresponding EU legislation as presented here and as it has been revised here. As copyrighters, they should create their own original work and not plagiarise the work of others. They should also protect the intellectual rights of their clients and make sure that their acts do not expose them to unauthorised use of intellectual property prosecutions. This could happen if the marketing agency uses text, images, graphics, photos, videos or data generated by others and have no permissions from the right holders. Everything an agency develops should be original, Nothing should be reposted or copied from any other source.
The client also agrees to respect the work produced from the agency. Yes, the client does own the end product but has no ownership on the intellectual rights of the creators. Thus there is no permission to modify, copy or reproduce agency work for other reasons than it was made for or in other time frames than it was originally designed and agreed to run without permission or consent from the agency.
The following statement can help you realise how powerful the intellectual assets of a company can be. The CEO of one of the largest fast-food brands once said that if there was a natural disaster and they were to loose all assets overnight they could borrow the money to build back everything again on the next day only using the value of their brand. This happens because all those years of investing on hard marketing work has formed the perception of consumers associating this brand with specific values and behaviours they love. The value of that association can be clearly seen when estimating the monetary value of the top 100 global brands.