"The investment drive started about a year ago, he [Bloomberg journalist, Jonathan Ferzinger] says, after it had become clear that tunnels were the only way to beat the Israeli blockade.
'All sorts of stuff was going under the border, everything from iPods to cows,' he told the BBC's World Update programme.
'As this became the only going enterprise in Gaza, people saw it as an investment opportunity.'
"Whatever compensation deal is reached with the investors, it is clear the tunnellers are not going away."
"Mr [Omar] Shaban [director of the Gaza-based economic research institute Pal-Think] stresses that the Israeli blockade is at the heart of the problem.
It has created an 'economic structure that is neither registered nor documented nor transparent,' he says."