Lenin explains it in Imperialism as the Highest State of Capitalism (emphasis mine):

Finance capital is interested not only in the already discovered sources of raw materials but also in potential sources, because present-day technical development is extremely rapid, and land which is useless today may be improved tomorrow if new methods are devised (to this end a big bank can equip a special expedition of engineers, agricultural experts, etc.), and if large amounts of capital are invested. This also applies to prospecting for minerals, to new methods of processing up and utilising raw materials, etc., etc. Hence, the inevitable striving of finance capital to enlarge its spheres of influence and even its actual territory. In the same way that the trusts capitalise their property at two or three times its value, taking into account its “potential” (and not actual) profits and the further results of monopoly, so finance capital in general strives to seize the largest possible amount of land of all kinds in all places, and by every means, taking into account potential sources of raw materials and fearing to be left behind in the fierce struggle for the last remnants of independent territory, or for the repartition of those territories that have been already divided.