* CME raises wheat futures (W) initial margins for specs by 16.7 percent to $1,925 per contract from $1,650
* CME raises soybean futures (S) initial margins for specs by 15 percent to $2,530 per contract from $2,200
* CME raises soybean meal futures (06) initial margins for specs by 15.8 percent to $2,420 per contract from $2,090
* CME raises corn futures (C) initial margins for specs by 25 percent to $1,375 per contract from $1,100
The rates will be effective after the close of business on Wednesday, July 01, 2015