The bourgeoisie is the ruling class in capitalist society which owns the means of production and has decisive influence over economic production. It extracts surplus value from the labor power of the working class.
In the early development of capitalism, freed and escaped serfs settled in towns. They joined the guilds and eventually started their own small businesses which led to the creation of the proletariat, especially with the abolition of slave and feudal (serf) labor. However, due to the laws of capitalist development, over time the bourgeoisie became more and more consolidated and capital more and more accumulated.
By the late 19th century capitalism had eaten itself. Where once the bourgeoisie had a free market and competition; where once it was at the beck and call of state authority; whereas the decentralized nature of production (small craftsmen, etc) carried with it a higher level of anarchy in production– the rapid and irreversible accumulation and monopolization of capital decimated small business and free competition of bourgeois enterprise; monopoly capital, further, corrupted and subsumed the state; production became more streamlined and mass production was introduced; cartels, syndicates, and trusts formed to monopolize raw resources for production and squeeze out smaller competitors. With the augmentation of capital into finance capital, banks (cartelizing and monopolizing themselves) and other monopolies erected a new scheme to make money from money (interest) on an international scale. This is what is meant by Marxist-Leninists when they reference the "international bourgeoisie". The world's land and other resources were to follow the same process of development– free resources were to be plundered by foreign nations and the land carved up by monopoly landholders through competition and consolidation. This was the impotus for the first world war, or the first inter-imperialist war.
In the 20th century, the British bourgeoisie was far surpassed by its American cousins. When the October Revolution established a Russian dictatorship of the proletariat and refused to pay debts to European banks accrued under the Tsar and interim (bourgeois democratic) government, the international bourgeoisie vowed to destroy the Soviet Union. They sent funds to the White Army, sent their paratroopers and their footsoldiers to invade and assist the White Army, and much more. When none of these could defeat the Soviets, the British bourgeoisie used finance capital to build up a threat against them; and what better threat than an impoverished, nihilistic, and financially captured state like Germany after the first inter-imperialist war? Nazi Germany was supported by the international bourgeoisie against the Soviets as late as 1938– but the Nazis sought to destroy their own masters as well.
Following the second inter-imperialist war, the bourgeoisie used finance capital, covert operations, and other tactics to subvert socialist development by the proletarians of every nation. However, capital, previously tied to the gold standard even as finance capital, completed it's transition to abstract valuation by discarding the gold standard. The bourgeoisie now controlled (for the most part) it's own regulatory and legislative bodies in the state; it rapidly monopolized the resources and production; and now also controlled the money supply and value of capital itself. The Federal Reserve is the backbone of such a system based in the American Multipolarity.
The bourgeois socialists who, according to Marx and Engels, were already becoming in the late 1800s a full-fledged system of charities, foundations, animal rights activists, NGOs, and reformers of all kinds, enlarged with the development of imperialism (finance capital) to the point where they could champion reforms and minimal concessions for the working class under the guise of revolutionary slogans. Higher education, think tanks, trusts, foundations, charities, and political parties were infused with finance capital so as to kill class consciousness in its cradle and lead it to the logger where it has taken root. The discourse itself began to be monopolized by the bourgeoisie– the age of information warfare burgeoned; and with the onset of the internet, massive multinational corporations could remotely coordinate the discourse and daily experiences of most of the world. This bourgeois socialism became dominant, and on such foundation rests part of Haz Al-Din's claim that "We already live in socialism", that today the struggle is against this false notion of socialism and for an authentic socialism based in the proletariat and great masses of each nation (the shared conditions of which, as class and as human, respectively, unite the inter-national working class) (See Socialist Patriotism).
The international bourgeoisie, now unrestricted by national or regional bonds, had only itself left to monopolize. The global monopoly of bourgeois power is only a further development, on the international scale, of the bourgeoisie, just as previously the industrial monopolists had replaced the small businesses and free market. These new institutions and structures of the "globalists" are best exemplified by the World Economic Forum (WEF), Bank of International Settlements (BIS), International Monetary Fund (IMF), implemented on Wall Street and in the City of London financial district.