Initial investments don't always lead to JV agreements. If the company is just looking at having a window into the decision making process of a foreign company a smaller investment (maybe around the 5% level... I don't know exactly) that gives a seat on the Board allows that. An example is Gol. We don't have a JV with them, hence no derivative contracts that are convertible to shares.

Pension fund investments are reported on SEC form 13F, but you won't find that info under an SEC search for DAL. The pension investment Delta made in Grupo Aeromexico (I think 4.9%) was reported on that form. Check the 2015 Aeromexico Annual report, page 19 for more info.

Discussions by Delta leadership about these sorts of investments occur at Board meetings which is why it is so important to have a seat on the Board. The voting seat was put in place as part of the DAL/NWA merger agreement.

I hadn't seen the info you posted via the above link, but a person does have to ask, "what is Delta going to use that $1 Billion for?" I mean we're drowning in cash. What need does Delta have for an extra $1 Billion?