Imperialism is a policy or practice by a nation where they expand their powers and their influents by colonization or by political or economic control. Lenin compared imperialism to capitalism. Financial imperialism is a mechanism where developed countries control over developing countries without occupying their land physically. In this kind of imperialism, one dominating country or powerful country make control over a weak or a poor country through trade and for this, they take consent for international trade from the top leaders of the victim country. And then they make an unfriendly environment in the countries are bordered to the victim country and create tension among them. Next, they target the youth of the countries and introduce their fashion and their products in the market. Then other things are also promoting and highlighted. They become used to it. Slowly-slowly people became slave voluntarily and get exploited. At the same time, domestic industry and business becomes out of the scene and could not be recovered from it.
Capitalism is the economic system where trade and industry of a country are controlled by private owners for profit. There is no control of Government as in case of imperialism.
As per Lenin's theory, Imperialism to the highest form of capitalism. I think because in imperialism everything is acquired like land, economy, resources, weapons etc. by the power or influence political, financial or economic control, military control. It includes the Government and the top leaders as well as the local economy. It starts with the trade to control the capital of a country. The basis of a capitalist society rests on competition but as per Grégoire Canlorbe, "Capitalism inevitably tends to a monopoly economy" — an economy in which there is no competition. Dominant companies stop the growth of other small companies and freeze competition in the monopoly environment.
As per Lenin, Finance capital increase profits through imperialist colonialism and the final stage is the development of capitalism. Finance capital occurs when banks merge with the industry and capitalism reaches an advanced stage and monopoly occurs.