Activist investor Paul Singer wants Qualcomm to pony up more cash in its bid to acquire NXP Semiconductors.

“We believe the current $110 offer is not even in the right zip code and a credible offer from Qualcomm requires a price in excess of our estimate of NXP’s intrinsic standalone fair value of $135 per share,” Singer’s Elliott Management said in a letter to NXP shareholders Friday.

NXP reps did not respond to requests to comment.

The letter came soon after San Diego-based Qualcomm announced its bid to buy NXP won antitrust approval from eight of nine foreign regulators.

Elliott has a 6.6 percent stake in NXP and has been publicly agitating for higher sale price since August.

Qualcomm reps declined to comment on Elliott’s letter.