Given the input sentence, please extract the subject and object containing a certain relation in the sentence according to the following relation types, in the format of "relation1: word1, word2; relation2: word3, word4". Relations include: 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.

Improving the dark pool while winding down retail market-making is part of Mahajan’s overhaul strategy, which is based on winning business from quantitative hedge funds that already are clients of other parts of Goldman Sachs, such as the prime brokerage.

Answer: industry: prime, retail