JPMorgan Chase disclosed Friday that losses on its botched credit bet could climb to more than $7 billion and that the bank’s traders may have intentionally tried to obscure the full extent of the red ink on the disastrous trades.

Mounting concerns about valuing the trades led the company to announce that its earnings for the first quarter were no longer reliable and would be restated. Federal regulators, who were already examining the trades, are now looking at whether employees of the nation’s biggest bank by assets intended to defraud investors, according to people with knowledge of the case.

The revelations left Jamie Dimon, the bank’s chief executive, scrambling for the second time within two months to contain the fallout from the trading debacle. It has already claimed one of his most trusted lieutenants, compelled Dimon to appear before Congress to account for the blunder, and prompted the bank to claw back millions in compensation from three traders in London at the heart of the losses. A top bank official said that the board could also seize pay from Dimon but did not indicate it would do so.

Since announcing initial losses of $2 billion in May, Dimon, once vaunted for his risk prowess after navigating the bank deftly through the financial crisis, has worked to prove that any flaws in risk management are limited to the chief investment office, a once-obscure unit with offices in London and New York. But the latest news is prompting fresh questions about whether risk controls throughout the bank are weak.

“This points to fundamental and potentially widespread risk management failure,’’ said Mark Williams, a professor of finance at Boston University, who also served as a Federal Reserve Bank examiner.

Much more than profits are at stake for Dimon. The mounting problems from the soured bets strengthen the hand of lawmakers in Washington who have been pushing to curtail the kind of risk-taking that led to the trading losses.

The possible deceptions came to light in a regulatory filing early Friday just before the bank reported its second-quarter earnings. While the bank posted a profit of nearly $5 billion despite the trading losses of $4.4 billion for the quarter, some analysts and regulators zeroed in on the valuation of the trades.

“If traders misrepresented a fact with the intent to defraud, they can be subject to criminal charges,’’ said Alan R. Bromberg, a securities law expert at Southern Methodist University.

In contrast, investors appeared to accept Dimon’s pledges that the bank had rooted out the problems and could reap record annual profits. They rallied behind the bank, sending its shares up nearly 6 percent, the best among its peers on an overall strong day for American stocks.

If the trades had been properly valued, the bank said it would have lost $1.4 billion on the position in the first quarter, bringing the total losses to $5.8 billion so far this year. In a conference call with analysts Friday, Dimon said that the trade, under the worst market conditions, could result in another $1.7 billion in losses.

In a rare move, the bank seized millions in pay from three managers in the unit’s London office who had ‘‘direct responsibility’’ for the blunder. People with knowledge of the clawbacks said that pay was taken back from Achilles Macris, Javier Martin-Artajo, and Bruno Iksil, the trader who gained fame as the London Whale for large credit trades.

While the company did not indicate the total tally for the clawbacks, Doug Braunstein, the bank’s chief financial officer, said the bank could claim about two years of compensation, including stock options.

Ina R. Drew, the senior executive who resigned as head of the chief investment office shortly after the trading losses, volunteered to give back her pay. Drew earned about $14 million last year.