Blackstone, Starwood REITs draw SEC’s attention after limiting withdrawals. Regulators looking into recent moves to slow investors’ redemptions .

Blackstone also released its first-quarter results on Thursday, reporting earnings of $481.3 million, up 31 percent from the same period last year. Its shares rose nearly 8 percent Thursday.

Just days before Investa Office Fund unit-holders were due to vote on a Blackstone takeover, Oxford launched a 3.3-billion Australian dollars ($3.1-billion) hostile bid for Investa.

Blackstone executives decided the hassle of converting into a C corporation and dealing with additional taxes was worth the benefits of shedding the partnership structure. So far, however, such a ...