What is the relationship between Morgan Stanley and investment bank in the context of the input sentence. Choose an answer from: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

Fitbit was buoyed on Tuesday by an upgrade from Morgan Stanley after analysts with the investment bank found that the maker of wearable devices had maintained market share despite increased competition from Apple.
product_or_material_produced