Time Warner Cable reportedly is looking to buy Insight Communications, the nation’s ninth-largest cable operator, for about $3 billion. Bloomberg says that the deal — which is in the advanced stages of negotiations, according to sources, and could be announced as soon as tomorrow — would be the cable giant’s biggest since the nation’s No. 2 cabler (behind Comcast) was spun off from Time Warner in 2009. The acquisition would make sense for TWC, which despite its stellar second quarter financially is losing subscribers in its core pay TV business, dropping 130,000 subs in that service during 2Q. Those numbers would get a boost with Insight and its 679,700 basic cable customers in Kentucky, Indiana, and Ohio. Carlyle Group took the lead in taking Insight private in 2005; last year, Crestview Partners and MidOcean Partners took stakes.