HSBC entered into a nonprosecution agreement with the Justice Department and agreed to a $101 million penalty to settle an investigation into whether it used confidential information to manipulate currencies ahead of transactions on behalf of the bank's clients, according to documents made public Thursday.

The agreement, posted to the docket of the U.S. District Court for the Eastern District of New York late Thursday, shows the deal is related to previous actions against the former head of the bank's global foreign exchange cash trading, Mark Johnson. Johnson was convicted in October of numerous wire fraud counts in the Eastern District.

Thursday's revelations show Johnson's actions connected directly to HSBC itself, while detailing another scheme that prosecutors said showed the bank profited handsomely from the front-running trading practice.

In the documents released Thursday, prosecutors detailed the scheme Johnson was convicted of. At the center of it was HSBC's handling of a currency exchange transaction for Cairn Energy from the $3.5 billion sale of an Indian subsidiary. In October 2011, HSBC won the contract to handle the transaction, promising not to take any actions based on the confidential information about the transaction to convert dollars to pounds.

Ahead of the actual transaction, HSBC employees, including Johnson, openly discussed “ramping up” the currency market in a way that wouldn't make Cairn suspicious. Traders at the bank began buying up British pounds in anticipation of the transaction. When the actual transaction occurred in December, Johnson and others orchestrated front-running purchases of the currency ahead of the announcement.

All told, HSBC generated some $8 million in profits from the front-running scheme. Before and after the transaction, Johnson and others at HSBC continually provided Cairn with misleading information in an attempt to hide their fraudulent actions.

HSBC was represented by Davis Polk & Wardwell.

In a separate scheme detailed in the court documents, an unnamed company was likewise the victim of front-running. In February 2010, HSBC traders again used confidential information to make $34.8 million for the bank.

Prosecutors charged the bank with two counts of wire fraud. HSBC entered into a three-year deferred prosecution agreement and accepted responsibility for its actions. The bank agreed to pay a $101.5 million penalty, including a $63.1 million fine and $38.4 million in restitution. The payment reflected a 15 percent reduction in recognition of HSBC's cooperation and remediation, according to the bank.

“HSBC is committed to ensuring fair outcomes for our customers and protecting the orderly and transparent operation of the markets,” a spokesman for the bank said in a statement. “Since the historical conduct described in the agreement, we have strengthened our controls in the global markets business, and we will continue to make further improvements.”