NEW YORK — US bank JP Morgan Chase was slapped with fines and repayment penalties of $228 million for a bid-rigging scheme that shortchanged issuers of municipal bonds, US authorities announced Thursday.

In a case that has also seen Swiss bank UBS and Bank of America heavily fined, JP Morgan admitted that employees of JP Morgan Securities (JPMS) conspired to manipulate the bidding process for the right to handle the proceeds of billions of dollars in muni bond auctions between 2001 and 2006.

The payout covers penalties, restitution of $51.2 million to the affected borrowers and disgorgement of profits on the deals, according to the Department of Justice and the Securities and Exchange Commission.

In parallel agreements with state and federal authorities, the company avoided being legally prosecuted on the charges while admitting to anticompetitive conduct.

Eighteen former employees of banks and financial service firms have been hit with criminal charges in the scheme, and nine have pleaded guilty, including former JP Morgan executive James Hertz, the Justice Department said in a statement.

JP Morgan's involvement in the ring tied it to at least 93 bids which were fraudulently fixed in 31 states, according to the SEC.

The bids were for the right to reinvest the proceeds of the bond sales before the funds were to be utilized by the issuers, mostly US municipalities.

"JPMS improperly won bids by entering into secret arrangements with bidding agents to get an illegal 'last look' at competitors' bids," said Robert Khuzami, director of the SEC's enforcement division.

"Municipal issuers and investors didn't stand a chance against the fraudulent strategies JPMS and others used to guarantee profits."

In May UBS agreed to pay $160 million in fines and restitution in the same case, and Bank of America settled its role in the ring for $137 million last December.