Bloomberg -- Massachusetts sent subpoenas to 15 brokerages including units of Bank of America Corp., Morgan Stanley and Wells Fargo & Co. as it investigates alternative- investment sales to seniors.

The probe will examine how investments such as real-estate investment trusts, oil and gas partnerships, private placements and structured products are marketed to seniors, Secretary of the Commonwealth William Galvin said today in a statement.

“While these products are not unsuitable in and of themselves, they are accidents waiting to happen when they are sold to inexperienced investors by untrained agents who push the products to score the large commissions,” Galvin said in the statement.

Galvin’s office, which settled in May with five brokerages over improper sales of REITs to seniors, is trying to determine the extent of alternative investment sales to seniors and if they comply with Massachusetts regulations.

“Being included on the list is not an indication of wrongdoing at this time,” Galvin said.

The investigation is looking into sales by independent broker-dealers as well as those by banks, discount brokers and asset-management companies.

Galvin’s office said in the statement that it sent subpoenas to units of Morgan Stanley, Bank of America, Wells Fargo, UBS AG, FMR LLC, Charles Schwab Corp., TD Ameritrade Holding Corp., ING Groep NV, LPL Financial Holdings Inc, Commonwealth Financial Network, MML Investor Services Inc., Investors Capital Corp., Signator Investors Inc., Meyers Associates LP and WFG Investments Inc.

Spokesmen for the firms declined to comment or didn’t immediately reply to requests for comment.