(Reuters) -Nasdaq, which hosts some of the biggest U.S. tech giants on its exchange, said on Monday it was investigating an issue related to connectivity and stock orders, marking its second technical glitch in months.

The company did not give details about the severity of the issue, but said it was related to the matching engine - software systems that match buy and sell orders on an exchange. The incident started around 4.55 a.m. ET, according to the exchange's website.