ROME, Aug 27 (Reuters) - Fintech group ION"s vehicle Castor Bidco said on Friday it had raised by 7% to nearly 2 billion euros ($2.35 billion) its bid to buy out investors in Italy"s Cerved as it seeks to take control of the credit data and information group. Dublin-based ION, led by Italian businessman Andrea Pignataro, in March announced an 1.86 billion euro takeover offer for Milan-based Cerved, compared with the new offer of 1.99 billion euros. Only days before the initial offer, ION had bought Italian banking software provider Cedacri and bankers say a combination of the two groups would make industrial sense, although ION has said it supports Cerved"s current growth plans. Castor Bidco is offering 10.20 euros for each Cerved share tendered, up from an initial 9.50 euros, which the stock has mostly traded above since April. Cerved"s board had rejected the offer as too low. Cerved opened up 1.4% at 10.09 euros per share, outperforming the wider market, which was slightly down. ION"s new offer represents a premium of 53.6% on the share"s average price over the 12 months before the date of the announcement of the offer, the group said in the statement, compared to the 43% premium it initially offered. Castro BidCo also said that it had extended the period of the tender, started in mid-July, to Sept. 9. It said it had raised the minimum threshold condition to a stake of 80% from 50% plus one share. ($1 = 0.8498 euros)