Is it correct to say:
"I have worked at Microsoft, Apple and currently Google"
meaning you've recently worked in the first two companies, and now in the third one?
Other examples:
"I have been a student in Paris, Rome, Madrid and currently London"
"I have written poetry, fiction and currently newspaper articles"
Thus, the combined statement of the three companies at which he's worked, with the qualifier for the current place of employ, is just fine.
However, the Oxford Comma following "Apple" is missing. In contrast, unless he left the company and then returned later, he could not say "I had worked at Google"
– Monty Harder Sep 13 '17 at 19:49