Entity types and names of China’s companies in Latin alphabet
There is a great deal of flexibility in the writing of registered company names.

Geely—浙江吉利控股集团有限公司
Sinopec—中国石油化工集团公司
Tencent—腾讯控股有限公司

As you can see, these famous companies do not just transliterate their Chinese names into Pinyin, but come up with a more English-sounding name instead.
Wikipedia has a page on the entity types for Chinese companies. It would be ambiguous to use abbreviations like YG and GYG, since there is no true distinction between words in Chinese. A lot of Chinese people like to abbreviate “word for word”, like YXGS and GFYXGS for the examples you have brought up.