Source: Sharecast
Citing people following the situation, Betaville said there were rumours that Aviva has attracted interest from a company looking to purchase the business.
However, the identity of the company circling Aviva is unclear. Previous reports have suggested German insurance group Allianz has looked at buying a blue-chip London-listed insurer, such as Aviva.
French insurance giant Axa has also been acquisitive in the past, Betaville noted, having paid $15bn for Bermudan-based XL Group in 2018.
Other insurance firms that have been acquisitive in the UK insurance market include Canada's Intact Financial Group and Scandinavian firm Tryg, it said. They paid £7.2bn for London-listed RSA in 2020.
Intact Financial Group also recently bought Direct Line's brokered commercial lines operations for an initial payment of £520m to bolster its UK operations.
At 0940 BST, the shares were up 9% at 423.42p.
Russ Mould, investment director at AJ Bell, said: "Chatter that foreign players Allianz, Intact Financial and Tryg are among the potential interested parties has fired up the shares, hot on the heels of a bullish broker note earlier this week.
"What might they see in Aviva? Well, the business is forecast to have strong free cash flow and excess capital and its valuation is cheap. It has slimmed down in recent years to focus on the stronger parts of the group and there is now an opportunity to increase its position in bulk annuities which looks like a more prosperous market thanks to higher gilt yields.
"Activist investor Cevian Capital is no longer on the shareholder register causing mischief and Aviva is left as one of many stocks on the UK market looking unloved but still offering the potential for long-term value generation.
"One of the obvious times to buy a company is when it has made solid progress with a turnaround programme as that de-risks the investment case. Aviva has cast off the shackles of being a conglomerate and sharpened its focus as a result of asset disposals and a new impetus to grow, making it a stronger business. Naturally, that makes it more appealing to a would-be suitor."