* Exchange looking at share spike before J&J deal - WSJ
* Synthes shares trade near flat (Adds J&J declines to comment)
June 15 (Reuters) - Swiss Stock Exchange officials are investigating an unusual jump in the shares in Swiss medical device maker Synthes Inc SYST.VX before its takeover by Johnson & Johnson (JNJ.N), the Wall Street Journal said.
If the investigation brings any evidence of insider trading, stock market officials could refer the case to Zurich's prosecutor, the newspaper said, citing people familiar with the matter.
The Journal added that the inquiry is in the early stages and may not lead anywhere.
Synthes shares were little changed at 147.6 francs at 1023 GMT, while the European healthcare index was up 0.44 percent.
J&J was reported to be in preliminary talks to buy Synthes for about $20 billion after the market closed on April 15. [ID:nN15294408]
Synthes, J&J and the Swiss Stock Exchange declined to comment when contacted by Reuters. (Reporting by Vaishnavi Bala in Bangalore; Editing by Elaine Hardcastle and Greg Mahlich)