Bankia SAU, the commercial lender formed from a merger of Spanish savings banks, will delay registering its initial public offering prospectus until next week, said a person with knowledge of the matter. The stock market regulator has asked for additional information and the lender wants to add extra details before registering the prospectus on Monday or Tuesday rather than yesterday, said the person, who declined to be identified because the decision isn’t public. The lender still aims to start trading in Madrid in mid-July, the person said. Bankia, a lender with 272 billion euros ($392 billion) in assets, is attempting to raise capital from equity investors at a time when concern about a possible default by Greece and mounting bad loans linked to domestic real estate have driven up borrowing costs for Spanish banks and the state. Bankia, which has taken 4.5 billion euros from a government bailout fund, will need another 1.8 billion euros to meet new minimum capital rules if it lists its shares and 5.8 billion euros if it doesn’t. A Bankia spokeswoman said she couldn’t comment on the IPO plans.