Robinhood, TDAmeritrade, and other online stock-trading platforms all experienced issues on Monday

• Robinhood, TDAmeritrade, Schwab, and Vanguard all experienced issues on Monday.
• In many instances, users reported problems logging into their accounts, placing trades, or having them executed.
• Short outages are typical, though a sustained, industry-wide issue is rare.
• Also on Monday, Bloomberg reported Robinhood was being investigated by US authorities over an outage it experienced earlier this year. A spokesperson declined to comment on the report.

Several major online brokerages and trading platforms were rocked by service interruptions during trading Monday.

Robinhood, TDAmeritrade, Charles Schwab, and Vanguard all said they had experienced some form of issues or slowness on their websites.

Robinhood, the extremely popular online brokerage, said its issues were resolved around 12 p.m. Eastern after customers logged thousands of reports beginning shortly after 8 a.m through the opening of trading.

TDAmeritrade said that many of its clients had experienced "high levels of slowness" on its web platforms affecting logins. The issues have been fixed, it said.

Schwab and Vanguard also said they were experiencing issues Monday, and by late afternoon not yet said they were resolved.

Discrete outages are common for online brokerages, if not many websites across the web. However, as Bloomberg points out, a coinciding outage is rare. According to the news site, the US Securities and Exchange Commission as well as an industry self-regulatory body are investigating another major outage experienced by Robinhood earlier this year. A spokesperson declined to comment on the reported investigations.