Google's John Mueller answered a question on Twitter on spam report. The question was what happens when a competitor of yours continues to report your site as spam. John Mueller implied you do not have to worry.
He said your placement won't drop in Google solely because your competitor is continually reporting your site as spam.
Here are the set of tweets:
@Bruce_Neville @googlewmc No. pic.twitter.com/feOllVTRmW
— John Mueller (@JohnMu) July 21, 2016
Of course, if you are spamming and Google looks into the spam report, it can and should negatively impact your rankings. But if you are clean, then you won't be hurting.
Forum discussion at Twitter.