Where to submit malware & suspicious files to Microsoft
You can submit the file directly to Microsoft using this webpage at the Malware Protection Center. It is always recommended that you zip the file and send it in compressed form.
Where to submit virus & malware files to antivirus companies
If you want to submit virus & malware files to antivirus companies, here are a few links that will help you:
AviraAvastAdAwareAhnLabAVGAviraComodoEsetEmsisoftF-SecureKasperskyMcAfeeMalwarebytesSymantec (Retail) | Symantec Security ResponseSophosTrend MicroUS-CERT.
If you know of any more, please do share!