The state may have more money on hand than expected for this fiscal year, according to state Comptroller Kevin Lembo, who announced Monday that revenue has increased by $414.9 million since last month.

In his monthly letter   to Gov. Dannel P. Malloy, Lembo said the state will end the fiscal year with a $509.6 million surplus. But the comptroller said the additional funds should not impact the current budget and the only reason the state has a surplus instead of a $1.6 billion deficit is because it used $2.1 billion in one-time revenue to balance the budget.

“This revenue should be used to diminish debt and replenish the Rainy Day Fund,” he said. “This should not be used as an opportunity to increase spending.”

Lembo reiterated what he told the Appropriations Committee in March—the state needs to cushion its “Rainy Day Fund” to protect itself against uncertain financial markets. The law only dictates the state must maintain the fund at 10 percent of its budget, but Lembo said 15 percent would better protect taxpayers.

Lembo also encouraged lawmakers who are considering eliminating the energy assessment. He said the additional revenue also could allow the state to reverse the policy without creating a huge funding gap.

“This revenue offers an opportunity to reverse bad public policy and rescind an assessment targeting electric ratepayers,” he said. “This electric assessment is an added burden for Connecticut electric consumers already paying the highest electric rates in the continental United States. Legislative leaders are rightfully reconsidering a charge that targets electric ratepayers, and now have an opportunity to implement this reversal.”