Did the US ever try to out purchase raw materials vs Germany?

So I’m reading a fiction novel about some minor level WWII espionage, and one of the side subjects is about a neutral country supplying raw materials to Germany (Portugal and Tungsten).

Made me wonder if the US ever tried to purchase more of the raw materials from countries to undermine the ability of Germany, Italy, or Japan of getting raw materials.

Being as Germany got most of its raw material from territories it already controlled or occupied there was likely no direct or indirect buying from these territories by the US.

As it was the US already had access to vast resources and had no need of raw materials from countries that supplied Germany.

The part about the US having the materials is where I was wondering about undermining Germany- there were enough resources that theoretically, the US had the ability to hoard materials from all over the world- preventing Germany from getting them.

But Germany did get raw materials from countries that were neutral- such as tungsten from Portugal- who traded both with the allies as well as Germany- but had to do it very carefully to avoid being drawn into the war- being invaded from either side.

A lot of countries that stayed neutral throughout the war especially those in South America tended to lean towards the Germans as even then the US was viewed poorly by those countries due to US trying to exert control over them. Even near the wars end it was not uncommon for neutral ships to leave South America loaded with raw materials for Germany which while it was well known they were headed for Germany the materials were often bought through third parties headed to places like Spain, Sweden and he Mediterranean countries which then would make port of calls elsewhere to unload cargo.

It was a big game of cat and mouse with very high stakes involved.

German is Achilles heel was oil production something that the US could theoretically control the market on which could of hurt the Germans but there are a ton of what if’s involved there too.